16 – 21 June 2024
Leiden, the Netherlands

TALKS & POSTERS

During the sessions, you can choose from a selection of 175 talks. The oral presentations are divided into 11 Plenary Talks sessions and 14 Parallel Talks sessions spread across three rooms:

  • Grote Zaal
  • Breezaal
  • Aalmarktzaal

 

Additionally, there are over 500 posters to view in the 4 poster rounds.

If multiple presentations are scheduled in 1 session round, there will be no room change; participants are expected to attend all presentations in that session. 

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Monday 17 June 2024

08:00 - 17:50 Poster round 1

3D Simulations of Haze from Earth-like Exoplanets to Hot-Jupiters

Poster210Mei Ting Mak; University of Exeter

Poster AreaMon 08:00 - 17:50

We present results from 3D simulations of photochemical haze ranging from rocky exoplanets to hot Jupiters. Photochemical haze is a solid-state product formed from photo-dissociation of gases. It was expected to be present in the atmosphere of the Early Earth and exoplanets. Here we use the 3D general circulation model - the Met Office Unified Model - to study and compare the radiative and dynamical effect of haze on the climate of Early Earth, TRAPPIST-1e and a representative hot Jupiter. We found global warming and cooling on rocky planets when the haze layer is thin and thick, respectively. A thermal inversion of our simulations is present in the upper atmosphere due to strong absorption of shortwave radiation by haze. We also present new results from simulations of hot Jupiters including interactive haze treatments.

Atmospheres
3D GCM, habitability, Haze

A close companion to a hot Jupiter?

Poster445Jan-Vincent Harre; German Aerospace Center (DLR), Institute of Planetary Research

Poster AreaMon 08:00 - 17:50

We report observations with the CHEOPS space telescope revealing TTVs on the order of 30 s of an ultra hot Jupiter, consistent with a low-order resonance. This indicates the existence of a close-by non-transiting (mini-) Neptune or super-Earth. Due to the relatively low RV precision caused by fast rotation, the companion could not be discovered in the RVs. Further evidence for the existence of the companion is given by a small eccentricity of the hot Jupiter’s orbit, measured from occultation timings. Systems like this are very rare, with only a handful having been discovered yet, and challenge our understanding of the formation and migration processes that shape these systems.

RV and transits
CHEOPS, Orbital decay, Photometry, Transit timing variations

A Close-in Neptune Orbiting a Very Low Mass Star Challenges Formation Models

Poster257Gudmundur Stefansson; University of Amsterdam

Poster AreaMon 08:00 - 17:50

Theories of planet formation predict that planets as massive as Neptune to be rare around very low-mass (VLM) stars. Using near-infrared radial velocity observations, we report the discovery of a Neptune mass planet orbiting the nearby VLM star LHS 3154 which has a mass of 0.11 Solar masses. The planet's orbital period is 3.7 days and its minimum mass is 13.2 MEarth, giving it the largest known planet-to-star mass ratio among short-period planets orbiting VLM stars. Both the core accretion and gravitational instability theories of planet formation struggle to account for the system. In this talk, we place the surprisingly massive planet in context of other known planetary systems orbiting VLM stars, and we present planet formation simulations showing that planets such as LHS 3154b are only formed if the protoplanetary dust disk mass is substantially higher than typically observed around VLM stars.

RV and transits
M stars, Planet Detection

A Deep HST/WFC3/H-alpha Imaging Survey to Probe the Demographics of Accreting Planets at Wide Separations

Poster292Lillian Jiang; The University of Texas at Austin

Poster AreaMon 08:00 - 17:50

Current direct imaging surveys of exoplanets are limited by their reliance on thermal emission, resulting in a biased understanding of exoplanet demographics. Hot-start planets, which have higher luminosities during planet formation, are thus favored over cold-start giant planets, which are fainter and difficult to detect. Similarly, sub-Jovian-mass planets at wide separations remain largely unexplored. H-alpha emission from accreting planets can provide an alternative approach to estimate planet occurrence rates regardless of their thermal evolution and enables the search for lower-mass planets. Here, we present initial results from a deep HST/WFC3-UVIS H-alpha imaging survey of over 200 cluster members of ~2Myr star-forming region IC348. We employ a novel machine learning strategy to identify nearby point sources after PSF subtraction, which has resulted in several candidate accreting planets that are well-suited for follow-up observations. Ultimately this study will provide the first demographic constraints on an otherwise hidden population of long-period accreting protoplanets.

Demographics & Architectures
Accreting Planets, Machine Learning, Planet Demographics, RDI

A New Era in Exoplanet Characterization with the Habitable Worlds Observatory

Poster452Searra Foote; University of Arizona

Poster AreaMon 08:00 - 17:50

The under-development NASA Habitable Worlds Observatory (HWO) will provide breakthroughs in exoplanet science, especially in regards to characterization and the search for habitability and life. We aim to help quantify search and characterization metrics through the use of EXOSIMS, an exoplanet yield modeling tool used for direct imaging missions. For the first time, EXOSIMS will provide statistical constraints on broad atmospheric characterization metrics and give more information about atmospheric archetypes. Through development and use of this modeling tool, we will generate planetary atmosphere compositions in EXOSIMS for synthesized planet populations. Then, we will incorporate and cross-validate an ultra-fast planetary spectrum generation and atmospheric characterization tool. We can then draw conclusions about how different HWO architectures could constrain key comparative planetology quantities.

Future missions/instrumentation
exoplanets, NASA Habitable Worlds Observatory

A Search for Transiting Exosatellites in JWST Panchromatic Substellar Lightcurves

Poster218Mary Anne Limbach; University of Michigan

Poster AreaMon 08:00 - 17:50

JWST has monitored the panchromatic lightcurves of half-a-dozen brown dwarfs, FFPs, and wide-orbit exoplanets. The observations provide characterization of weather on these distant worlds with precisions never before achieved, but this high-precision dataset also introduces the unprecedented opportunity to search for transiting exomoons and satellites. Transit injection/recovery tests with the lightcurves demonstrate the ability to detect exosatellites smaller than Jupiter's Galilean moons. We show that if JWST continues to monitor substellar and exoplanet lightcurves at the current pace, we stand on the cusp of discovering an exomoon or satellite well within the first decade of JWST operations. The prospective discoveries are poised to illuminate an unexplored parameter space of host-companion demographics, bridging the gap between the Trappist-1 and Jovian systems. We discuss how this new population may be markedly different than the known population of exoplanets and the transformative potential these findings could have on our understanding of extrasolar systems.

JWST Results
Exomoons

A search for transiting planets around hot subdwarfs

Poster516Antoine Thuillier; Université de Liège

Poster AreaMon 08:00 - 17:50

Hot subdwarfs (sdOB) are small post-Red-Giant Branch (RGB) stars that experienced a dramatic loss of their enveloppe at the tip of the RGB. Their small size (0.1-0.3 Rsun) make themideal candidates to probe the fate of close-in planets during the RGB using the transit method. In my talk I will present our project dedicated to the search for transiting planets around sdOBs, using TESS, Kepler and CHEOPS data. Our goal is to compute the occurrences of planets around sdOBs and bring observational constraints to the theoretical works regarding planetary engulfment. Thanks to the short lifetime ofsdOBs, it is less likely that close-in planets would have enough time to migrate or form as second generation bodies, and would correspond to bodies that were engulfed during the RGB phase. I will provide the results and occurrence rates from our analysis of more than a thousand sdOBs.

Star-planet interactions
PostRGB stars

An ESPRESSO view of the HD 189733 system

Poster504Eduardo Cristo; Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP

Poster AreaMon 08:00 - 17:50

The characterization of exoplanets involves various techniques that enable us to reveal the subtle signatures left by planets in the signal of the host star. One ground-based method that has received relatively little exploration is the chromatic-Rossiter McLaughlin (CRM), capable of utilizing Radial Velocity (RV) observations during transits to extract broadband transmission spectra [1, 2].

In our study, we employed the CRM technique implemented in CaRM [3] to extract the transmission spectrum of HD 189733b using ESPRESSO [4] observations. We utilized an enhanced RM model, which includes the effect of differential rotation and convective blueshift, to achieve better accuracy. The wavelength range of ESPRESSO was subdivided into smaller bins, and our RM model was used to calculate the wavelength-dependent planetary radius. The resultant transmission spectrum reveals a trend of decreasing radii with increasing wavelength, a feature commonly associated with the presence of haze in the atmospheres of exoplanets.

Atmospheres
Atmospheres, Orbital Architecture, RossiterMcLaughlin effect, Stellar Surfaces

An unlikely survivor: a low-density hot Neptune orbiting a red giant star

Poster220Samuel Grunblatt; Johns Hopkins University

Poster AreaMon 08:00 - 17:50

Hot Neptunes, gaseous planets smaller than Saturn (~3-8 R_Earth) with orbital periods less than 10 days, are rare. Models predict this is due to high-energy stellar irradiation stripping planetary atmospheres over time, often leaving be- hind only rocky planetary cores. We present the discovery of a 7.3 R_Earth (0.62 R_Jup), 19.2 M_Earth (0.060 M_Jup) planet transiting a red giant star every 4.21285 days. The old age, high equilibrium temperature and low density of this planet suggest that this planet has lost a relatively large fraction of its initial mass, making its retention of such a low density atmosphere surprising. Unexpectedly low stellar activity and/or late-stage planet inflation could be responsible for the observed properties of this system.

Formation and evolution
atmospheric inflation, atmospheric mass loss, postmain sequence

ARDA: A 3D Atmospheric Modeling and Retrieval Code for High Spectral Resolution Phase Curves

Poster106Peter Smith; Arizona State University

Poster AreaMon 08:00 - 17:50

Recent improvements in instrumentation and computational methods have unlocked a wealth of information in high spectral resolution (R > 15,000) data of transiting exoplanets. Current data of hot- and ultra-hot Jupiters is of high enough quality that three-dimensional effects, such as from thermochemical gradients and winds, can manifest in the data. However, 1D retrieval frameworks have struggled to keep pace. Here, we present ARDA - Atmospheric Retrieval via Disk Averaging - a 3D atmospheric modeling and retrieval code accelerated by GPUs to be fast enough for high spectral resolution retrievals. ARDA can map analytic global pressure-temperature and velocity fields, calculate vertical gas abundances, and perform radiative transfer extremely fast, allowing the estimation of longitudinal thermal structure and wind speeds from high resolution spectroscopic phase curves. We also present preliminary results applying ARDA to combined data sets from Gemini South/IGRINS and JWST/NIRISS of the ultra-hot Jupiter WASP-18b.

Atmospheres
atmospheric retrieval, high resolution spectroscopy

Are there planets around hot subdwarfs?

Poster491Valerie Van Grootel; ULiège

Poster AreaMon 08:00 - 17:50

Hot subdwarfs experienced strong mass loss on the red giant branch (RGB) and are now hot (20,000-40,000 K) and small (0.1-0.3 Rsun) stars. These objects are in a phase of core-He burning that will last for about 100 Myr. They constitute excellent targets for addressing the question of the evolution of exoplanetary systems directly after the RGB phase. To date, several planet detections around hot subdwarfs have been claimed, but none of them received confirmation.In this talk I will discuss the tentative planets claimed around hot subdwarfs, and I will present first results of a transit survey in all light curves of hot subdwarfs observed from space (Kepler, K2, TESS, and CHEOPS). The goal is to compute meaningful statistics on two points: firstly, the occurrence rates of planets around hot subdwarfs, and secondly, the probability of survival for close-in planets engulfed during the RGB phase of their host star.

Formation and evolution
Evolution after the RGB phase, Starplanet interactions

Assessment of He I triplet absorption at 10830Å in escaping atmospheres of hot gaseous exoplanets

Poster357Anna Taylor; Lunar and Planetary Laboratory, University of Arizona

Poster AreaMon 08:00 - 17:50

Atmospheric escape in hot gaseous exoplanets can now be studied using high-resolution absorption measurements of the He I triplet line at 10830 Å on many exoplanets. However, the metastable He I triplet line transit observations are often difficult to understand. For example, for the archetype hot Jupiter HD209458b, the observed transit depths are much shallower than predicted by typical escape models. As a result, it has been suggested that the He abundance in the planet’s envelope must be significantly lower than solar, a conclusion that would also explain observations of other planets. However, the interpretation of the observations involves assumptions about atmospheric structure and the excitation/de-excitation of atomic helium. We present an in-depth assessment of related excitation/de-excitation processes and use a multi-species hydrodynamic code coupled with photochemistry and lower/middle atmosphere models to better explain the He I triplet transit observations.

Atmospheres
Atomic Processes, Hot Jupiters

Astroclimes - describing the capabilities of our synthetic transmission spectra code for removing telluric lines

Poster401Marcelo Aron Fetzner Keniger; University of Warwick

Poster AreaMon 08:00 - 17:50

Proper removal of telluric lines is essential to achieve good precision and unbiased measurements of atmospheric abundances and temperatures of exoplanets via high resolution cross-correlation spectroscopy. Yet, there is still no single established method for correcting telluric spectra.

We develop a new code for generating synthetic transmission spectra, which would allow us to remove telluric lines. The transmission spectra is modelled from molecular cross-sections, an atmospheric profile and a radiative transfer equation. We demonstrate the code's efficacy in removing telluric lines from data from numerous instruments in the visible and infrared range, for several spectral types.

One aspect that sets our code apart from similar ones in the literature is that we also hope to use it to measure the amount of greenhouse gases in the Earth's atmosphere. So, our goal is not only to remove telluric lines, but to fit them as well.

Other
Synthetic transmission spectra, Telluric lines

Atmospheric inhomogeneities and observational degeneracies from CRIRES+ observations of the hot Jupiter WASP-189b

Poster464Fabio Lesjak; Institut für Astrophysik und Geophysik Göttingen

Poster AreaMon 08:00 - 17:50

Atmospheres of hot Jupiters are complex systems characterised by cloud formation, inhomogeneous distributions of molecules, fast winds and disequilibrium chemistry. WASP-189b is one of the hottest exoplanets with a detected atmosphere, and a prime candidate to study these effects due to its strong emission signal.

We have observed the day-side emission spectrum of WASP-189b with CRIRES+ in the K-band, and present the results of an atmospheric retrieval. We first searched for emission of individual species using the cross-correlation method, resulting in a strong CO detection and evidence for other species. Different peak positions in the velocity space give insight into the inhomogeneous distributions of molecules across the planetary surface. Then we applied a Bayesian retrieval framework and retrieved the temperature-pressure profile, C/O ratio and other atmospheric parameters. We analyse the inherent degeneracies between different atmospheric parameters, providing a comprehensive understanding of the complexities within the atmosphere of WASP-189b.

Atmospheres
High resolution

Attractor reconstruction of active stellar light curves

Poster411Emily Sandford; University of Cambridge

Poster AreaMon 08:00 - 17:50

Stellar activity is notoriously difficult to model, being neither periodic nor purely stochastic. In light curves, the interplay between the stellar differential rotation and the evolution of spots and faculae gives rise to quasi-periodic modulation over timescales of hours to weeks. Despite this complexity, light curves often bear strong qualitative resemblance to systems known to exhibit low-dimensional dynamical chaos, such as the Rössler attractor. In the 1980s-90s, a suite of techniques for nonlinear dynamical analysis, called attractor reconstruction, evolved to study exactly this type of system. Attractor reconstruction has been used successfully to model the historical sunspot record and the light curves of variable stars (both simulated and observed) and to recover information about their underlying dynamics, including their dimensionality and the time scales over which they can be meaningfully forecast into the future. Here, I discuss the application of attractor reconstruction to the light curves of active main-sequence stars.

RV and transits
Methods, Time series analysis

Characterisation of the atmosphere of WASP-76b using SPIRou

Poster148Thea Hood; IRAP

Poster AreaMon 08:00 - 17:50

The near-infrared spectropolarimeter SPIRou located at the Canada-France-Hawaii Telescope is one of the best for atmospheric characterisation of exoplanets from the ground, due to its properties and location. It observed WASP-76b following a reported and confirmed asymmetry in the limbs of its atmosphere, detected through observations in the visible (Ehrenreich et al. 2020). This led to extensive theoretical and observational work around this planet to understand its peculiarity. In acquiring infrared data of this atmosphere, different species and pressure layers are expected to be probed, which could reveal different temperature and dynamical profiles of the atmosphere. I will detail my study of the characterisation of the atmosphere of WASP-76b using SPIRou data and how it led to the detection of H2O and CO. Such detections open a new window into the understanding of the dynamics, physics and chemistry of WASP-76b, and new insight on ultra-hot planetary atmospheres.

Atmospheres
Methods: data analysis, Planets and satellites: atmospheres, Techniques: spectroscopic

Characterising Polluted White Dwarfs with Machine Learning to Probe Extrasolar Geochemistry

Poster421Mariona Badenas-Agusti; Massachusetts Institute of Technology

Poster AreaMon 08:00 - 17:50

Between 25-50% of white dwarfs exhibit heavy elements in their atmospheres, likely from the accretion of exoplanetary material. These “Polluted” White Dwarfs (PWD) provide a unique opportunity to directly constrain the elemental abundances of their accreted bodies and learn about extrasolar compositions more broadly. To date, there are more than 1000 of such systems, yet only a few dozen have been characterised with high-resolution spectroscopy. To help unlock large-scale studies of PWDs, we have developed Cecilia, a fast and efficient Machine Learning (ML) pipeline to accurately (≲0.1 dex) determine the elemental abundances of PWDs from their spectra. We have leveraged two large astronomical databases to increase the number of PWDs, and we have used Cecilia to measure the bulk composition of a few heavily polluted systems. Automated methods like Cecilia, combined with data from upcoming massive astronomical surveys, can open the door to a statistical understanding of extrasolar geochemistry.

Interiors
compositions, spectroscopy, white dwarfs

Characterising the Atmospheric Properties of WASP-43b Using Phase-Resolved Spectroscopy

Poster119Jingxuan Yang; University of Oxford

Poster AreaMon 08:00 - 17:50

We retrieved the chemical and thermal properties of WASP-43b by simultaneously fitting emission spectra observed at multiple orbital phases with JWST’s MIRI/LRS instrument [1]. Assuming that the atmosphere is well-mixed, we independently retrieved the volume mixing ratios of molecules using a parametric global atmospheric model validated with synthetic data simulated from GCMs [2,4]. We precisely constrained the H2O abundance and found strong evidence for NH3 and moderate evidence for CO. The retrieved molecular abundances are consistent with solar metallicity, in agreement with the expected planetary mass-metallicity relation. We also analysed the HST/WFC3 + Spitzer/IRAC phase curves of WASP-43b [3], which yielded consistent water abundance. Leveraging MIRI eclipse mapping, we conducted additional retrievals of the MIRI data set incorporating various latitudinal temperature distributions to retrieve the three-dimensional thermal structure of WASP-43b. Our analysis characterises the atmosphere of WASP-43b with exceptional clarity, setting a solid foundation for future observations.

JWST Results
Atmospheric Retrievals, Eclipse Mapping, Phase Curves, WASP43b

Characterizing long-period massive companions in multiple systems

Poster227Alessandro Ruggieri; University of Padova

Poster AreaMon 08:00 - 17:50

Due to selection effects, most currently known planets have low-to-intermediate periods. However, long-term RV monitoring allows the search for longer-period planets for some targets when combined with other methods like astrometry and direct imaging. In this work, we considered 16 Sun-like stars with at least one already known planet with a > 1 au, and we found that 3 of them had an additional outer massive companion but no inner ones. The identification and characterization of these candidates have been possible thanks to the combination of our long-term RV monitoring with HARPS-N, Gaia DR3, and literature imaging data. One of the objects is very promising for direct detection with already scheduled SPHERE observations (expected to be performed by the time of the conference), with significant improvements compared to the preliminary parameters by Feng+2022. Interestingly, one of our systems undergoes a peculiar and unique dynamic evolution, possibly in stable chaos.

Demographics & Architectures
Planets and satellites: detection, Stars: solartype, Techniques: miscellaneous

Characterizing the exoplanetary atmosphere by modeling its H-alpha and He 10830 transmission spectra

Poster405Dongdong Yan; Yunnan Observatories, Chinese Academy of Sciences

Poster AreaMon 08:00 - 17:50

Escaping atmosphere has been detected by the excess absorption of Lyα, Hα and He triplet (λ10830) lines. Simultaneously modeling the absorption of the Hα and He λ10830 lines can provide useful constraints since the two absorption lines are basically thermospheric in origin. Here, I will show our work of modeling of H-alpha and He 10830 transmission spectrum of a hot-Jupiter, which helps to constrain the stellar XUV and Ly-alpha flux, H/He ratio and mass loss rate of the atmosphere, and provides clues to the escaping atmosphere of hydrogen and helium. We use XUV driven hydrodynamic simulation to obtain the atmospheric structures, solve the rate equations of non-local thermal equilibrium to calculate the detailed level population, and then conduct the radiative transfer simulation to model the transmission spectrum. The Monte Carlo simulations of Ly-alpha radiative transfer are performed to calculate the Ly-alpha mean intensity, necessary in estimating the hydrogen level population.

Atmospheres
exoplanetary atmosphere Halpha and He 10830, transmission spectra

Chasing for new proxies of the magnetic activity with SPIRou

Poster419Paul Charpentier; IRAP - CNRS

Poster AreaMon 08:00 - 17:50

Recent instruments have extended radial velocity observations from the optical to the near-infrared. This has in particular allowed the study of M dwarf stars, known to host a higher frequency of rocky planets. However, to search for planets around such stars, investigating the stellar magnetic activity is crucial. Indeed, the precision of spectrometers depends on both photon noise and intrinsic stellar variations. In this study, a selection of targets from the SPIRou Legacy Survey (SLS) was employed to identify new magnetic activity proxies. By comparing these with small-scale magnetic field measurements, we study the correlation with activity proxies. With the small-scale magnetic field being a well-established indicator that matches the RV activity jitter in solar studies, further studies of these new activity indicators have promising potential in filtering out RV stellar jitter to uncover low mass exoplanets.

RV and transits
Stars: magnetic fields, Techniques: spectroscopic

CHEOPS observations of KELT-20b: an aligned orbit and signs of variability from a reflective dayside

Poster370Vikash Singh; Osservatorio Astrofisico di Catania, INAF

Poster AreaMon 08:00 - 17:50

Occultations are windows of opportunity to indirectly peek into the dayside atmosphere of exoplanets. We aim to precisely measure the planetary radius and geometric albedo of the ultra-hot Jupiter KELT-20b as well as the system's spin-orbit alignment. We obtained optical high-precision transits and occultations of KELT-20b with CHEOPS in conjunction with simultaneous TESS observations. We further use the host star's gravity-darkened nature to measure the system's obliquity. We present time-averaged precise occultation depth of 82(6) ppm measured with seven CHEOPS visits, and 131(+8/-7) ppm from four sectors of TESS photometry. We interpret the occultation measurements together with archival infrared observations to measure the planet's geometric albedo and dayside temperatures. KELT-20b's comparably high geometric albedo corroborates a recent known trend of strongly irradiated planets being more reflective. Finally, we tentatively detect signs of temporal variability in the occultation depths, which might indicate variable cloud cover advecting onto the planetary dayside.

Atmospheres
Individual: KELT20b/MASCARA2b, Photometry: CHEOPS and TESS

Climatic evolution of molten super-Earths

Poster309Emma Postolec; University of Groningen, Kapteyn Astronomical Institute

Poster AreaMon 08:00 - 17:50

The atmospheric composition of gaseous and sub-Neptune exoplanets can now be identified thanks to JWST observations, but remains challenging for rocky planets such as super-Earths. Rocky planets atmospheres are molded by several phenomena: initial volatile budget, radiation from the host star, the escape of volatile species and more. On planets with largely molten planetary mantles, magma oceans, the volatile species present in the atmosphere, such as H2O or CO2, interact strongly with the interior through various processes like in- and outgassing. Escape mechanisms strongly shape the chemical evolution of magma ocean atmospheres. We aim to estimate the average molecular weight of each volatile species in the atmosphere of lava planets, evolving on geologic timescales. We use a coupled interior-atmosphere model to simulate the evolution of rocky planets during the magma ocean era, focusing on the dominant fractionation induced by the interaction between volatile escape and outgassing from the planetary interior.

Atmospheres
Magma ocean, Rocky exoplanets, Superearths

Clouds and hazes in the era of next-generation exoplanet data

Poster255Sushuang Ma; University College London

Poster AreaMon 08:00 - 17:50

The analysis of exoplanetary spectroscopic data recorded by Webb and other space- and ground-based facilities has reminded us of the importance of modelling correctly clouds and hazes. Retrieval studies have been central to interpreting observed spectroscopic data, especially those obtained with Hubble and Spitzer. However, clouds and hazes are often too crudely parametrized in current retrieval models and are inadequate to interpret higher-quality data such as those provided by Webb. Here, I will introduce YunMa (Ma et al. 2023), a cloud and haze radiative transfer model which includes elements of cloud formation and microphysics tailored to address these challenges. YunMa can be used as a stand-alone model or embedded in the TauREx spectral retrieval framework. In my presentation, I will show simulations of different types of clouds and hazes in exoplanet transit spectra and reflect on the possibility of retrieving clouds’ and hazes’ features from Webb and Ariel data.

Atmospheres
Clouds and hazes, Exoplanetary atmospheres, Retrieval techniques

Comparative Planetology of Magnetic Effects in Ultrahot Jupiters

Poster196Hayley Beltz; University of Maryland

Poster AreaMon 08:00 - 17:50

Ultrahot Jupiters (UHJs) represent the hottest class of exoplanets known. These planets are expected to host magnetic fields, which will shape their atmosphere and their resulting emission and transmission spectra. Using a state-of-the-art kinematic magnetohydrodynamic (MHD) approach in a 3D numerical model, we study three different ultrahot Jupiters with and without magnetic effects. The inclusion of kinematic MHD results in a "magnetic circulation regime", distinct from the typical circulation seen in UHJs. We post-process these models to generate high resolution emission and transmission spectra and explore trends in net Doppler shifts to identify observational strategies for detecting magnetic effects in high resolution spectroscopy. This work provides important predictions critical for understanding the atmospheres of the hottest planets.

Atmospheres
GCM, high resolution spectroscopy, magnetism, ultrahot Jupiter

Condensation in atmospheres of hot, rocky planets

Poster166Leoni Janssen; Leiden Observatory

Poster AreaMon 08:00 - 17:50

JWST allows for the first time to observe atmospheres of rocky exoplanets including the well-studied Hot Super Earth 55 Cnc e. If cloud formation takes place, this could affect gas composition on the planet, dim spectral features or change the temperature structure in its atmospheres. Observation of silicate clouds could also point to the presence of a magma ocean. Hence, it is important to understand cloud formation on magma planets, to interpret spectroscopic information accurately.To investigate this, we have run a grid of models for atmospheres of magma planets by coupling the outgassing with equilibrium chemistry taking into account condensation. We then iterate the results with radiative transfer for self-consistent TP-structures. In this talk I will present the results of our grid calculation focusing on the type of condensable species in these worlds, the conditions for them to form and their effect on the atmosphere.

Atmospheres
analytical, condensation, magma planets

Confronting Composition Confusion through the characterisation of the sub-Neptune orbiting TOI-1778.

Poster37Larissa Palethorpe; University of Edinburgh

Poster AreaMon 08:00 - 17:50

When plotting a mass-radius diagram of confirmed exoplanets, there is a region with a degeneracy between water-worlds and planets with a hydrogen-rich atmosphere. We report on the properties of TOI-1778 b, a planet residing in this region. We combined 99 HARPS-N RVs, two TESS sectors, and two CHEOPS transits with a GP for stellar activity, and find that the planet has a moderately eccentric orbit, a period of 6.5 days, a mass of ~8.5 Earth masses, and a radius of ~2.8 Earth radii. These indicate a sub-Neptune with a H/He atmosphere that is about ~1% of the total mass and a ¼ of its radius, largely ruling it out as a water-world. The characterisation of TOI-1778 b, adding to the small sample of well-characterised sub-Neptunes, is an important step forwards on our journey to understanding planetary formation and evolution pathways, and constraining the compositional confusion that currently surrounds small exoplanets.

RV and transits
planets and satellites: compositionplanets and satellites: detection

Coupling atmospheric retrieval to interior characterization for Super-Earths and Sub-Neptunes

Poster412Maria Oreshenko; ETH Zurich

Poster AreaMon 08:00 - 17:50

We present a novel framework to couple interior modeling with atmospheric retrieval. This allows us to use JWST data together with mass & radius data to unravel the nature of planets. Specifically, we focus on the detection of water and its consequences for the deeper water content in mantle and core and apply our methodology to HD 3167b and GJ 1214b. Even small amounts of atmospheric water (mixing ratio of 0.01) can lead to constraints of tens of percents of water in the deep interior. We show how sensitive the water content of the interior is to simulated water detections in the upper atmosphere and if it is possible to constrain a minimal amount of water in the interior for a given detection precision, which plays an important role for present and future JWST observations.

Atmospheres
Coupling interior and atmosphere, water content

DETECTABLITY OF WATER VAPOR ON TERRESTRIAL EXOPLANETS AROUND GK STARS WITH TIANLIN

Poster358Wei Wang; National Astronomical Observatories, Chinese Academy of Sciences

Poster AreaMon 08:00 - 17:50

China has proposed a space telescope with aperture size of 6 meters named Tianlin (a Chinese word meaning “neighbors in the sky”), which is dedicated for the characterization of rocky planets in the habitable zones (HZ) around nearby GK stars. It will be equipped with a low to high resolution spectrograph and a high contrast coronagraph. We conduct a preliminary simulation of transmission and reflected spectra for Earth-like planets around G, K type stars and perform retrieval analysis of the detectablity of H2O, a key bio-indicating molecule. Our results show that Tianlin has the ability to constrain H2O abundances in the atmosphere of Earth-like planets in most cases for a 5-yr time span. Importantly, we point out that higher spectral resolution can largely improve the detection capability and the significance the water vapor abundance assessment. In this talk, I will present the simulation results of our concept study in details.

Future missions/instrumentation
exoplanetary atmosphere, space mission, terrestrial planets

DIPSY: A new Disc Instability Population SYnthesis

Poster535Oliver Schib; University of Bern

Poster AreaMon 08:00 - 17:50

test

Formation and evolution
Disc Instability

Discovery of NIR Gas Emission with JWST/NIRSpec in a Debris Disk

Poster263Cicero Lu; NSF's NOIRLab, Gemini Observatory

Poster AreaMon 08:00 - 17:50

We carried out a survey to search for signatures of warm gas due to exocomets in a sample of disks where hot and cold gas co-exist (JWST Cycle 1, PI: Rebollido, PID 2053). I will present NIRSpec observations of the debris disk HD 131488. We discovered CO emission in the NIR corresponding to ro-vibrational modes. This is the first time that CO fundamental emission has been discovered in NIR for a debris disk. We identified the existence of 12CO and its isotopologue 13CO emission lines, and our analyses show a non-linear trend in the rotational excitation diagram. This could indicate the existence of two populations of gas, warm and cold, where the warm gas has a more compact spatial distribution than the cold gas. Alternatively, this may be an optically-thick, UV fluorescence emission of CO gas. I will discuss our interpretations and the need for follow-up data to break degeneracies.

JWST Results
Debris Disks, Gas

Early Solar System dynamical instability triggered by dispersal of the gaseous protoplanetary disk

Poster460Beibei Liu; Zhejiang University

Poster AreaMon 08:00 - 17:50

The Solar System’s orbital structure was sculpted by a dynamical instability among the giant planets, yet the trigger and timing have not been clearly established. We use dynamical simulations to show that the giant planets’ instability was likely triggered by the dispersal of the gaseous disk. As the disk evaporated from the inside-out, its inner edge swept successively across and dynamically perturbed each planet’s orbit. The associated orbital shift caused a compression of the exterior system, ultimately triggering instability. The final orbits of simulated systems match those of the Solar System for a viable range of astrophysical parameters. The giant planet instability took place as the gaseous disk dissipated, constrained by astronomical observations to be a few to ten million years after the birth of the Solar System. The growing terrestrial planets may even have been sculpted by its perturbations, explaining the small mass of Mars relative to Earth.

Formation and evolution
solar system evolutiongiant planet migration

Effects of UV Radiation on Sub-Neptune Hazes Through Laboratory Experiments

Poster394Lori Huseby; University of Arizona, Lunar & Planetary Laboratory

Poster AreaMon 08:00 - 17:50

Planetary hazes are formed when gasses are dissociated or ionized by high energy radiation, undergo subsequent chemical reactions, and form solids suspended in the atmosphere. However, the evolution of these photochemically-produced hazes are only beginning to be understood through laboratory and theoretical experiments. We have completed the first laboratory experiments analogous to post-formation stellar UV irradiation for sub-Neptune exoplanet hazes. We subjected two “water world” laboratory-made hazes to two different bandpasses of UV irradiation to assess evolution under stellar flaring activity. We obtained both reflectance and transmission spectra of the irradiated hazes across a broad wavelength range (from FUV to mid-IR, 0.2-15μm). We discuss changes seen during the irradiation process, changes to specific spectral features, and connections to molecule destruction and alteration. The results of these experiments will have observational implications for HST and JWST, which can help us understand haze evolution in sub-Neptune exoplanet atmospheres.

Star-planet interactions
Exoplanet HazesLaboratory ExperimentsWater WorldsUV Flaring Events

ESPRESSO observations of K2-106b and the properties USPs

Poster170Eike Wolf Guenther; Thüringer Landessternwarte Tautenburg

Poster AreaMon 08:00 - 17:50

Ultra-short period planets (USPs) are an enigmatic subset of exoplanets with orbital periods less than one day. Several formation scenarios have been proposed. They might be the eroded cores of gas-giants. Another possibility is that they formed as rocky planets at large distance and migrated inward, either via disk-migration, or via planet-planet interaction. Alternatively, they formed relatively close to the host star. Precise measurements of their densities constrain the various formation scenarios. USPs have the advantage that their masses and radii can be determined with high precision than for planets of longer period. As up to now, the masses and radii of 35 USPs with masses below 25 Earth-masses have been determined. Using ESPRESSO, we have recently redetermined the density of K2-106b. Putting these new measurements into the context of the density measurements of other USPs, we discuss how likely the various formation scenarios are.

RV and transits
Ultrashort period planetsplanet densityradialvelocity measurements

EXOAID : Artificial Intelligence for Exoplanet Detection and Characterization in the Gaia era.

Poster228Asier Abreu Aramburu; ATG Science And Engineering S.L.

Poster AreaMon 08:00 - 17:50

The current census of exoplanets has been almost entirely built upon transit and radial velocity detection methods. Astrometric exoplanet detection has been almost anecdotal so far due to the ultra-high (~as) precision required for this detection technique,but ESA's Gaia mission has radically changed the picture, paving the road for astrometric exoplanet detection at large and over the full-sky. Our project (ExoAID) aims to improve the current statistics and sky-coverage on detected exoplanets by application of deep learning techniques to the Gaia catalog, exploiting the correlation between the astrometric solution quality and the presence of a sub-stellar mass companion. We use synthetic data to train different neural network architecture to learn the underlying relation between those features and a binary class target (positive=candidate to host exoplanet/ negative=unlikely to host exoplanet detectable by Gaia) . The trained model can be used to produce a list of candidate stars to host exoplanets.

Microlensing and Astrometry
Astrometry, Deep LearningGaia

Exogeodynamics: simulating dynamical and thermal evolution of rocky exoplanets with various mantle mineralogy

Poster430Rob Spaargaren; University of Groningen

Poster AreaMon 08:00 - 17:50

Rocky exoplanets can have bulk compositions different from Earth's, leading to various metallic iron core sizes and mantle mineralogies. In this study, we explore how composition affects long-term interior evolution of a rocky planet for a number of representative bulk planet compositions, based on stellar abundances. We simulate interior evolution of 1 Earth mass rocky planets using a well-established geodynamical model, StagYY, accounting for mineralogy-dependent properties (e.g., density, viscosity) based on these planet compositions. Geodynamical simulations reveal a direct link between crust-mantle density contrast and mantle structure. Furthermore, we analyse how interior composition correlates to the likelihood that a planet has a thick, rigid lithosphere (crust + non-convective mantle) with limited atmosphere-interior interaction, versus Earth-like conditions where a mobile lithosphere allows extensive interaction between the atmosphere and the interior. Thus, we find that interior composition plays a role in the long-term interior evolution of rocky planets.

Interiors
Bulk rocky exoplanet composition, Geodynamics, Rocky exoplanets, Tectonic regime

Exoplanets as Drivers of Debris Disk Asymmetries: The Case of HD181327

Poster1647Chris Fox; University of Western Ontario

Poster AreaMon 08:00 - 17:50

The debris disk around HD181327 shows a significant asymmetry in visible light, an arc of approximately 90 degrees of higher density at 90.5 AU. This asymmetry has previously been interpreted as either a recent catastrophic disruption of a large body, or as interactions with the interstellar medium (Stark et al. 2014). Here we explore the possibility that an exoplanet could create such a density profile. Through the use of large N-body simulations, we demonstrate that this region of higher density can be explained by a Jupiter-mass planet orbiting near the inner edge of an exo-Kuiper belt that acts as a source of micron-sized dust grains.

Formation and evolution
Debris Disks, Simulations

Exotic Planet Candidates from Planet Hunters NGTS

Poster369Sean O'Brien; Queen's University Belfast

Poster AreaMon 08:00 - 17:50

Planet Hunters NGTS on Zooniverse enlists public volunteers to search for exoplanet transits in data from the Next Generation Transit Survey (NGTS), an array of twelve 20-cm telescopes that have been searching for transiting exoplanets since 2015. Volunteers are asked to classify the shape of transit-like features in the phase-folded light curves presented. Multiple volunteer assessments are combined through a weighting scheme to select candidates for further vetting checks by users and then by the NGTS science team. We will present a selection of the most interesting planet candidates discovered through Planet Hunters NGTS. These candidates have not been previously identified as NGTS planet candidates or TOIs. If confirmed, some of these candidates would present challenges to our understanding of planet formation with the potential discoveries of a close-in giant planet orbiting a low-mass star and a close binary hosting a planet on an S-type orbit.

RV and transits
citizen science, transit photometry

Exploring atmospheric escape with new spectral lines

Poster89Dion Linssen; University of Amsterdam

Poster AreaMon 08:00 - 17:50

Atmospheric escape can have crucial consequences for the evolution of exoplanets, and is thought to sculpt the hot Neptune desert and radius valley. The Lyman-α, metastable helium and several UV metal lines have presented evidence of escape for individual planets. Growing this sample of spectral lines that are used, as well as combining observations of multiple lines, will help us understand atmospheric escape in much greater detail. To this end, we make synthetic transit spectra and discover new spectral lines that should serve as good tracers of atmospheric escape, but have never been observed yet. We predict various lines with transit depths of up to tens of percent, which is stronger than some of the currently used tracers. Our model is open-source and available to the community, and can also be used to infer important outflow characteristics such as the mass-loss rate from observations.

Atmospheres
Modeling

Exploring Atmospheric Stability and Habitable Topography on Tidally Locked Rocky Exoplanets

Poster487Leonardos Gkouvelis; Ludwig-Maximilians-Universitat

Poster AreaMon 08:00 - 17:50

Atmospheric stability is fundamentally important for characterizing surface conditions on tidally locked rocky exoplanets. Radiation from the host star reaches one side of the planet, and various processes participate in the global heat redistribution of the atmosphere. In scenarios where, on the night side, the temperature drops below the condensation temperature of a gas, it condenses and forms an ice sheet at the planet’s surface in the cold trap. We explore the importance of mean molecular weight on circulation dynamics and atmospheric condensation on the night side. Using a 3D global climate model (GCM) coupled with multiphase chemistry, we simulate a selected sample of tidally locked rocky exoplanets for various scenarios. We introduce the term “habitable topography” for parts of the planet that can maintain temperate conditions under certain circumstances. Our exploration aims to identify atmospheric manifestations that may provide observables.

Habitability
Atmospheric stabilityhabitability, Rocky exoplanets, Tidally locked

Exploring Hidden Planet Formation: The JWST/NIRCam Coronagraphic Observations of the HD 163296 System

Poster355Taichi Uyama; California State University Northridge

Poster AreaMon 08:00 - 17:50

Directly imaging planets embedded in protoplanetary disks yields crucial insights into planet formation, evolution mechanisms, and planet-disk interactions. HD 163296, a young Herbig star, stands as an ideal testbed for exploring planet formation processes. High angular resolution observations from ALMA have unveiled numerous features suggestive of ongoing planet formation, including gaps in the dust continuum at ~0.1, 0.5, 0.9, and 1.5 arcsec from the central star (the two outer gaps coincide with CO gas depletion), and velocity perturbations in the CO gas at ~0.7 and 2.2 arcsec. Despite these indicators, however, previous ground-based high-contrast imaging efforts fell short in detecting companion candidates. To address this challenge, we undertook JWST/NIRCam deep coronagraphic observations in Cycle 1. In this presentation, we will show our post-processed results and engage in a comprehensive discussion to decipher their implications.

JWST Results
direct imaging

Exploring Ionospheric Conductivity in Giant Exoplanets: Implications for Magnetosphere-Ionosphere Dynamics and Energy Balance

Poster486Leonardos Gkouvelis; Ludwig-Maximilians-Universitat

Poster AreaMon 08:00 - 17:50

Conductivity is a crucial factor in the electrical coupling between planetary magnetospheres and ionospheres, significantly influencing the transfer of momentum and energy. While Hall currents are important, Pedersen conductivity plays a pivotal role in determining the amount of Joule power dissipation in the magnetosphere-ionosphere circuit. Our study explores the significance of ionospheric conductivity in gaseous giant exoplanets. We model ionospheric current flow from above and the closure of the magnetosphere-ionosphere circuit for various scenarios. We examine the generation and loss of ion species in the upper atmosphere and their importance in the energy balance. Our findings highlight the primary contribution to Pedersen conductance stemming from the collisions of ions with H2, underscoring its central role in controlling ionospheric current flow. We also explore atmospheric manifestations that can lead to observables.

Atmospheres
Giant exoplanets, Ionosphere, Upper atmosphere

Exploring the Lower Planet Size Boundary of Planetary Habitability

Poster393Michelle Hill; University of California Riverside

Poster AreaMon 08:00 - 17:50

How small can a planet be and still be considered habitable? While the upper size boundary of where a terrestrial planet becomes a gaseous planet has been studied in great detail1,2, there is yet to be a conclusive study that examines the lower planet mass and radius limit of habitability. This project will address this question to allow for improved prioritisation in upcoming exoplanet characterisation missions. We develop scaling laws for “sub-Earth” sized planets to determine when a planet may be considered to be too small to maintain liquid surface water. Scaling laws include a planet's thermal evolution, melt production, atmospheric composition, surface pressure, atmospheric escape, weathering rates and more. These scaling laws will then be incorporated into an existing model3,4,5,6 and the internal and external processes of Earth that are thought to be essential to maintaining habitable conditions will be explored. Preliminary results and next steps will be presented.

Habitability
Low mass, Modeling, Water

Exploring the observational and theoretical transition between Super-Earths and Sub-Neptunes around M and FGK-stars.

Poster252Léna PARC; University of Geneva

Poster AreaMon 08:00 - 17:50

With the updated PlanetS catalog of well characterized and reliable transiting planets, we revisit the bimodality of small planets orbiting M-dwarfs described by Luque & Pallé (2022) between terrestrial planets and water-worlds. By using more robust methods than the usual histograms, we draw the radius and density distribution of these planets and show the continuity of compositions between the two populations and the fading of the radius valley for low-mass stars. This enables us to explore the close connections between observations and theories related to the formation, evolution, and internal structure models. The study extends to FGK-dwarfs and the evolution of these results with the spectral type of the host star. Enlarging our samples is key to obtaining robust statistical results : we present the potential of the Near InfraRed Planet Searcher (NIRPS) spectrometer to determine and improve mass measurements of small planets in orbit around M-dwarf stars.

Demographics & Architectures
Density, Distributions, MR diagram, Observations vs Theories

Exploring the Origins of the Polar Planets

Poster79Ritika Sethi; Massachusetts Institute of Technology

Poster AreaMon 08:00 - 17:50

Many exoplanetary systems show significant misalignments between the orientations of their stellar spins and planetary orbits. Furthermore, the misaligned planets show preference to exist in nearly polar orbits, although the cause of this is still unclear. Roughly a third of the polar planets are Neptune or super-Neptune sized. They are relatively puffy and often found inside the “hot Neptune desert”. Their inflated radii could possibly be due to enhanced tidal dissipation owing to their highly oblique and moderately eccentric orbits. We will present ongoing work aimed at constraining the origins of polar Neptunes. Specifically, we construct atmospheric structure models to study the response of the planetary atmospheres to tidal heating, in an effort to quantify the degree of tidally-induced radius inflation. We will also present simulations that couple the orbital and interior/atmosphere models together and thus yield holistic constraints on the polar Neptunes’ past tidal history and long-term evolution.

Demographics & Architectures
Polar planets, spinorbit misalignment, tidal heating

Exploring the temperature profile of Jupiter's deep atmosphere

Poster168Louis Siebenaler; Leiden University

Poster AreaMon 08:00 - 17:50

Our understanding of the giant planets in our solar system has been significantly advanced by the Juno and Cassini missions. These planets provide us with the unique opportunity to understand the interior structure of giant exoplanets. Recent insight into Jupiter’s atmospheric composition indicates a water concentration of 2-7 times solar in the equatorial region, surpassing the subsolar findings of the precursor Galileo mission. In this study, we conduct radiative transfer calculations for Jupiter's deep atmosphere including these enhanced water enrichment results and the presence of condensates predicted by chemical equilibrium models. Our primary focus is to derive a new temperature-pressure profile and assess the existence of potential radiative zones within the deep atmosphere. The presence of a radiative zone can have a profound impact on the internal structure of a planet and thus, a detailed analysis of Jupiter's temperature profile is essential for a comprehensive study of its interior structure.

Atmospheres
Giant planets atmospheres, Jupiter

Forming Clouds with Theory and Laboratory Measurements

Poster469Erika Kohler; NASA Goddard Space Flight Center

Poster AreaMon 08:00 - 17:50

Refractory clouds would have a considerable impact on exoplanet atmospheric structure and composition but our ability to fully comprehend their effects requires laboratory data to advance atmospheric models and provide new model-data comparisons with improved observations. Our approach is to experimentally verify evaporation pathways, then use that knowledge to create a complete model for how clouds form on exoplanets. Among the refractory material candidates, we directly measured the saturated vapor pressure equilibrium of Zinc Sulfide (ZnS) in the laboratory, then characterized effects of the environment on the thermochemical equilibrium of condensation chemistry. Finally, we reevaluated ZnS cloud formation in exoplanet atmospheres based on this new data to see how it correlates to observational spectra. This project combines laboratory, theory, and modeling to provide valuable new insights into the physical and chemical processes that control cloud formation in exoplanetary atmospheres, enabling us to better understand the atmospheric properties of these worlds.

Atmospheres
Laboratory, Refractory Clouds, Vapor Pressures

From the desert into the savannah: a trek across the exo-Neptunes landscape

Poster202Vincent Bourrier; Department of Astronomy, University of Geneva

Poster AreaMon 08:00 - 17:50

Close-in exoplanets are shaped by complex atmospheric and dynamical processes, to which exo-Neptunes appear to be particularly sensitive. While atmospheric erosion played a major role in forming the Neptunian desert (a definite lack of Neptunes at short periods), it is not clear how far into the savannah (a milder deficit of Neptunes at longer periods) this process is active and when in a planet life it occurs. Determining the fraction of planets brought close-in by early disk-driven or late high-eccentricity migration is thus essential to understand their overall evolution. I will present the first results of ATREIDES, a large VLT/ESPRESSO transit program that will build the distribution of close-in Neptunes orbital architectures and disentangle their dynamical and atmospheric histories. The atmospheric screening further yielded by ATREIDES will provide the community with a catalog of candidates to follow-up with the JWST and ground-based spectrographs.

Demographics & Architectures
Evolution, Orbital architectures

GJ 526: A Search of Planets in Our Cosmic Backyard

Poster444Atanas Konstantinov Stefanov; Instituto de Astrofísica de Canarias

Poster AreaMon 08:00 - 17:50

M-dwarfs are the most abundant stars in our galaxy, and their low masses create attractive opportunities for exoplanet detection. One such star, GJ 526, lies in close proximity to the Sun. This star has a well-defined periodic activity, and its rotation period was recently constrained to about 48 days. There has been no evidence of planetary companions of GJ 526 – and the detection of one would add to the planetary statistics in the solar neighbourhood, which remains relatively unexplored. We use CARMENES, HIRES and high-precision ESPRESSO spectroscopic data to: (1) study the stellar activity of GJ 526, and most notably its rotation and possible magnetic cycles; (2) propose suitable indicators that describe the activity-induced RV signal; (3) detrend the RV timeseries to seek for low-mass planets. As GJ 526 is very nearby, any planet found at a moderate orbital period would be an excellent target for future atmospheric characterisation.

RV and transits
exoplanets, Mdwarfs, stellar activity

HARVY: A Highly-repeatable-Autonomous-extreme-precision-Radial-Velocity-facilitY concept to intensively search for Earth-twins and follow-up transiting planets.

Poster379Clark Baker; University of Cambridge

Poster AreaMon 08:00 - 17:50

The radial-velocity (RV) method is the only technique currently mature enough to search for Earth-twins without relying on the geometry of a transit. However, due to stellar-variability, the RV discovery of ‘Earth-like’ planets around solar-like stars will require intensive study of a single target ‘nightly’ over a period of ~10 years[1][2][3]. As such, a survey of ~20-30 targets of this type would occupy a large amount of a single telescope’s capacity for a decade; making large scale Earth-twin surveys, in general, unfeasible with current EPRV facilities.As such, there is a desire in the exoplanet community for a way to easily, cheaply and repeatably build numerous EPRV facilities.HARVY aims to achieve this by treating the telescope and EPRV-spectrograph as a single instrument optimised in throughput to study FGK-dwarfs. In this way, it would be feasible to systematically search for Earth-twins applying a low-cost facility using only 1.5m-class telescopes.

Future missions/instrumentation
Earth Twin, EPRV, Spectrograph

Henrietta: Updates on a new exoatmosphere spectrograph for Las Campanas Observatory

Poster1077Jason Williams; Carnegie Institution for Science

Poster AreaMon 08:00 - 17:50

We report on the status of Henrietta, a new near-infrared low-resolution (R ~ 200) spectrograph for the 1-meter Swope telescope at Las Campanas Observatory in Chile. Henrietta is uniquely designed to perform transmission spectroscopy of tens of exoplanet atmospheres per year across a wide bandpass and routinely reach the photon noise limit on a nightly basis. Henrietta is currently at Carnegie Observatories, where it will undergo optical assembly and alignment, as well as spectrophotometric testing to identify Henrietta's spectrophotometric noise floor. Upon finishing assembly and testing in Summer 2024, Henrietta will be shipped to Las Campanas Observatory where it will begin commissioning. In this talk, I will describe Henrietta’s science mission, its overall design, the results of current testing, its goals for commissioning and future opportunities for collaboration.

Future missions/instrumentation
Atmospheres, Groundbased, Instrumentation

Hot Jupiter - cold Jupiter. A complex sibling relation

Poster123Robert Wittenmyer; University of Southern Queensland

Poster AreaMon 08:00 - 17:50

The Solar system stands out from most known planetary systems. Detecting Jupiter-like planets helps unravel the uniqueness of the Solar system and sheds light on the formation of other planetary systems.

We present the discovery of a cold Jupiter in a system alongside a hot Jupiter. We investigate how changes in observation strategy can influence the ease with which such planets can be detected. By varying cadence and measurement precision, we estimate the additional data required to detect hypothetical cold Jupiters.

These systems are intriguing. Hot Jupiters are thought to form far away and migrate inward. Cold Jupiters can end in a distant and eccentric orbit, which could be the result of the influence of a third body that was ejected. To test this hypothesis, it is critical to search for additional planets in those systems. Our work will inform the best observation strategy to perform that search.

RV and transits
Cold Jupiter, Hot Jupiter

Impact of Dynamical Tides on Planetary System Stability: Evolution of Multi-Planet Systems

Poster124Leon Ka-Wang Kwok; Observatoire de Genève, Université de Genève

Poster AreaMon 08:00 - 17:50

Evolution models of planetary systems find that resonant chains of planets often arise from the formation within protoplanetary disks. However, the occurrence of observed resonant chains, such as the notable TRAPPIST-1 system, is relatively low. This suggests that the majority of these chains become destabilized after the dissipation of the protoplanetary disk. Stellar tides, especially the wavelike dynamical tide, could be proposed as potential contributors to the destabilization of resonant chains. The dissipation of the dynamical tide, because of the frequency-dependant tidal excitation of stellar oscillation eigenmodes, potentially leads to a boost in migration for the close-in planets and disrupts the fragile stability of resonant chains. Thus, we investigate the influence of the stellar dynamical tide on multi-planet systems with taking their dissipation into account in the N-body code Posidonius. Notably, this research represents the first exploration of the impact of frequency-dependent dynamical tides on multi-planet systems.

Star-planet interactions
Planetary Dynamics, Resonant Chains, Stellar Tides, Tidal Interactions

Inferring the empirical distribution of stellar tidal dissipation factors from citizen-scientist and professional transit observations

Poster269Lawrence Berry; University College London

Poster AreaMon 08:00 - 17:50

Transit timing variations may be indicative of tidal interactions between stars and planets. Several studies have already demonstrated evidence for tidal decay in hot Jupiters like Wasp-12b.By combining citizen-scientist observations from sources such as ExoClock together with professional ground and space-based observations, a larger dataset is available from which statistically significant inferences can be made about these tidal interactions.However, amateur data can be inaccurate due to experimental errors and in-homogenous light-curve modelling. To handle this, statistical techniques drawn from the field of Bayesian multivariate regression are used to improve outlier detection and adapt to uncertainty in the reported observational errors.This allows us to more tightly constrain well-known tidal decay candidates, identify promising new candidates, as well as build up an empirical distribution of the tidal dissipation factors of many stars, opening up avenues for further research into the relationships between tidal dissipation factors and other stellar properties.

Star-planet interactions
decay, tidal, transit, TTV

Interior-atmosphere coupling for super-Earths and sub-Neptunes

Poster67Komal Bali; ETH Zürich

Poster AreaMon 08:00 - 17:50

We explore interior models for Super-Earths and Sub Neptunes to better understand the diversity of their interiors and atmospheres. The majority of current interior models suffer from simplified assumptions of chemically inert interiors and the neglect of volatile-exchange at the rock-atmosphere interface. In our work, the presence of magma oceans and their chemical and compositional coupling with the atmosphere are of prime interest. We quantify their effects on mass-radius relationships and the consequences of using different interior models for the interpretation of bulk water and bulk H/He content. Our results show that estimates can vary by more than one order of magnitude. Our new interior models are essential tools for the interpretation of data, e.g., from Kepler, TESS, CHEOPS (and RV-follow-ups), but also JWST.

Interiors
interior atmosphere coupling

Investigate the Formation of Giant Planets Around M Dwarfs

Poster427Tianjun Gan; Tsinghua University

Poster AreaMon 08:00 - 17:50

Over the last two decades, hundreds of transiting giant planets are detected but only few of them are orbiting M dwarfs even if they are the most abundant stars in our Milky Way. With the highest planet-to-star mass ratio among planetary systems, giant planets around M dwarfs are the extreme cases to test planet formation theories and build a bridge with star formation. In this talk, I will present our statistical studies on the mass ratio and stellar metallicity distribution as well as occurrence rate of such systems. I will compare the observational results with predictions from theoretical works and investigate the formation channel. I will also present our preliminary result on the systematical search for transiting giant planets around late-type M dwarfs with TESS. Finally, I will discuss the origins of hot Jupiters around M dwarfs and the prospects in the JWST and Gaia era.

RV and transits
Demographics, Giant planets, M dwarfs

JWST NIRSpec transmission and emission spectra of the lava world K2-141 b

Poster81Amélie Gressier; Space Telescope Science Institute

Poster AreaMon 08:00 - 17:50

One of the key questions in exoplanetary science is to determine whether close-in rocky planets manage to retain atmospheres. A particularly exciting case is that of ultra-short-period, highly irradiated rocky planets, which have been predicted to give rise to exotic atmospheres --- unlike the ones observed in our Solar System. They provide, thus, a unique opportunity to explore the predicted compositional diversity resulting from outgassing and surface evaporation.Here, we present the first near-infrared transmission and emission spectra of the lava world K2-141b, a 1.58R⊕, 2.31M⊕, T˜2000K hot rocky exoplanet orbiting a K-dwarf star, with an ultra-short orbital period of only 7 hours. These precise measurements, obtained using the NIRSpec instrument onboard JWST (PID 2159; PI: Espinoza), allow us to put strong constraints on the atmospheric make-up of this lava planet, and an unprecedented view of these worlds between 3-5 μm.

JWST Results
exoplanet atmosphere, Lava planet, NIRSpec G395H, SuperEarth

JWST' first dive into a Water-World atmosphere

Poster390Amélie Gressier; Space Telescope Science Institute

Poster AreaMon 08:00 - 17:50

The observed small exoplanet population can be categorized into two sub-groups: Super-Earths (~1.3R⊕) and Sub-Neptunes (~2.4R⊕). Two atmospheric pathways account for this bi-modal distribution: highly irradiated planets may evolve into Super-Earths, shedding hydrogen atmospheres through mass loss, while Sub-Neptunes retain their atmospheres. Alternatively, the radius gap could be attributed to differences in bulk composition, suggesting the water-world existence hypothesis.Here, we present the first near-infrared transmission spectrum of a water-world, L98-59 d (1.58 R⊕, 2.31 M⊕, T˜400K), orbiting an M-dwarf. These precise measurements, obtained using one transit of the NIRSpec G395H instrument onboard JWST (PID:1224 PI; Stephan Birkmann), allow us to put unprecedented atmospheric constraints on these worlds from 3 to 5μm. Water, as well as carbon and sulfur-bearing species, exhibit absorption features in this wavelength range. These observations are crucial to confirming the existence of water-worlds and distinguishing between primary and secondary atmospheres.

JWST Results
data reduction, NIRSpec G395H, Waterworld

JWST/NIRSpec's transformative capability for direct spectroscopy of exoplanets

Poster272Jean-Baptiste Ruffio; University of California, San Diego

Poster AreaMon 08:00 - 17:50

JWST presents a unique opportunity to observe directly imaged exoplanets and brown dwarfs at wavelengths >3 μm and thereby better constrain their composition and atmospheric physics. I will present the first moderate resolution spectra with NIRSpec (R~2,700; 2.9−5.2 μm) targeting substellar companions at high contrast. This includes the benchmark T-dwarf HD 19467 B showing clear spectral features of CO2, CH4, CO and H2O (Fig. 1), the multi-planet system HR 8799, and the coldest imaged planet 51 Eri b. In order to mitigate systematics caused by spatial undersampling, we developed a framework to forward model the companion signal and host starlight directly in detector images. We demonstrated a sensitivity to companions that are 2x10-6 fainter than their stars at 1′′ (Fig. 2). The achieved performance will enable detailed spectroscopy of most known directly imaged exoplanets, and even allow spectroscopy of sub-Jupiters up to ~1 Gyr at 10 pc and 1’’ separation.

JWST Results
Exoplanet atmospheres

K2-155: a curious transiting system observed with Maroon-X

Poster488Nicola Nari; Light Bridges S.L.

Poster AreaMon 08:00 - 17:50

K2-155 is a K6-M0 star known for hosting three transiting planets, at periods of 6.34, 13.85, and 40.68 days, detected by the K2 mission. K2-155 shows a peculiar architecture in which the largest planet is the middle one, surrounded by potentially denser planets.

This configuration is difficult to create from a pure mass-loss scenario. We are observing this system with Maroon-X in a campaign lasting two semesters, to constrain the masses of all three planets. We will be able to perform a combined analysis of spectroscopy and photometry, taking into account activity indicators to disentangle signals of stellar and planetary origin. This will allow us to calculate their density and derive their composition, decoding fundamental information on the formation process of the system.

RV and transits
K2, MAROONXRV + transits

Know Thy Neighbor: Solar System Analog Observations for Exoplanet Science

Poster437Tyler Robinson; University of Arizona

Poster AreaMon 08:00 - 17:50

Interpretations of high-quality spectroscopic observations relevant to exoplanet atmospheric characterization—as are now arriving from NASA’s James Webb Space Telescope—require vetted tools. Additionally, using new observations to push the bounds of comparative planetology demands relevant comparison cases. Exoplanet analog observations and studies of solar system worlds, then, are a key avenue both for validating the types of models often used in exoplanet remote sensing and for yielding data for comparative planetology studies. Regarding validation, solar system observations are an opportunity to challenge exoplanet inverse models with real data for cases where the underlying atmospheric state is well-known. In this presentation we provide a review of available solar system exoplanet analog observations alongside a discussion of ongoing attempts to use these data to test approaches to atmospheric retrieval.

Atmospheres
Comparative Planetology, Planetary Atmospheres, Solar System

Large Interferometer for Exoplanets (LIFE): characterizing the mid-infrared thermal emission of terrestrial exoplanets

Poster147Tim Lichtenberg; University of Groningen

Poster AreaMon 08:00 - 17:50

The atmospheric characterization of a significant number of terrestrial exoplanets is a major goal of 21st century astrophysics. However, none of the currently adopted missions worldwide has the technical capabilities to achieve this goal. Here we present the LIFE mission concept, which addresses this issue by investigating the scientific potential and technological challenges of an ambitious mission employing a formation-flying nulling interferometer in space working at mid-infrared wavelengths. LIFE, in synergy with other planned future missions, will for the first time in human history enable us to understanding global biosignatures and planetary habitability in the context of the diversity of planetary systems. Breakthroughs in our understanding of the exoplanet population and relevant technologies justify the need, but also the feasibility, for future atmosphere characterization and life detection missions to investigate one of the most fundamental questions of humankind: how frequent are global biospheres in the nearby galaxy?

Future missions/instrumentation
biosignatures, diversity, exoplanets

Last updates on the CUISINES project

Poster197Thomas Fauchez; NASA GSFC

Poster AreaMon 08:00 - 17:50

The quickly growing field of exoplanet research has unveiled a vast tapestry of worlds. The exoplanet community has developed an impressive number of models to capture such diversity, from fast but simple 1D models to complex but slow 3D models.The Climate Using Interactive Suites of Intercomparisons Nested for Exoplanet Studies (CUISINES) is a project that aims to provide a structure to compare together those models. The idea is to leverage the success of the Coupled Model Intercomparison Project (CMIP) in Earth Science which plays a pivotal role in testing and comparing general circulation model (GCM) predictions of Earth global warming. By comparing models together, CUISINES can contribute to mitigate model dependencies, track down bugs and overall provide a more robust data prediction and interpretation for the observing community.In this presentation we will provide an update on the various CUISINES projects, currently in their third year.

Atmospheres
exoplanets, intercomparisons, radiative transfer

Like a wrecking ball: understanding giant planets as the key to finding Earths

Poster478Rob Wittenmyer; University of Southern Queensland

Poster AreaMon 08:00 - 17:50

To find truly Earth-like planets, we must understand Jupiter-like planets.

Cold giant planets appear to be correlated with small inner planets.

Nearly 200 cold giant planets are known from radial-velocity planet

searches. But their true masses remain unknown due to the limitations of

the technique. Gaia astrometry, paired with the radial velocities, permits

measurements of 3-dimensional architecture for these systems. We show

examples of Jupiter analogs for which this analysis has made surprising

revelations. Understanding full system architectures is critical for

modelling their dynamical histories.

The presence of giant planets can also disrupt the orbits of inner

habitable worlds. Surprisingly, archival radial-velocity data remain

unable to exclude giant planets near the habitable zone for many nearby

stars to be targeted by future direct imaging surveys such as NASA's

planned Habitable Worlds Observatory. We present results of simulated

observing campaigns to determine optimal strategies for thorough vetting

of candidate target stars.

Habitability
habitability

Magnetic winding and turbulence in ultra-hot Jupiters

Poster47Clàudia Soriano Guerrero; INSTITUTE OF SPACE SCIENCES

Poster AreaMon 08:00 - 17:50

Hot Jupiters have been considered as natural candidates to harbour intense magnetic fields, both due to their large masses which might empower a larger internal dynamo, and, possibly, due to their high energy budgets coming from irradiation. In this talk we focus on the latter aspect and perform MHD simulations of a narrow day-side atmospheric column of ultra-hot Jupiters, suitable for very high local temperatures (T ≳ 3000 K). Due to the high conductivity in this regime, the primary influence is the winding of the magnetic field caused by the intense zonal winds. In our study, we include a forcing that mimics the wind profiles observed in GCMs near the sub-stellar point. As a result, the shear layer generates a toroidal magnetic field, locally reaching few kG, which is supported by meridional currents.

Atmospheres
Hot Jupiters

Magnetohydrodynamical torsional oscillations from thermo-resistive instability in hot jupiters

Poster39Raphaël Hardy; Université de Montréal

Poster AreaMon 08:00 - 17:50

Magnetized atmospheres of hot jupiters host a thermo-resistive instability. This phenomenon is a new source of variability in these planets. With the right conditions, it can even reverse the equatorial winds and displace the hot spot westward of the substellar point.

We present a model with typical stratification of a hot jupiter atmosphere including temperature and time dependent electrical conductivity. We find solutions susceptible to the thermo-resistive instability with low to moderate equilibrium temperatures (Teq≈1000-1200 K). The instability requires the system to oscillate between weak and strong magnetic coupling.

The temperature dependence of the electrical conductivity is an important ingredient that should be included in magnetohydrodynamic models of hot jupiters dynamics. Moreover, I will show new results from our latest model, which considers longitudinal variations. It yields predictions of the hot spot behavior during the onset and unfolding of the instabilities with periods of ∼months, potentially detectable by JWST.

Atmospheres
magnetic fields, magnetohydrodynamics, variability

MASCARA: does it help your eyelash?

Poster49Swaetha Ramkumar; Trinity College Dublin

Poster AreaMon 08:00 - 17:50

The exoplanets discovered so far have added a host of weird worlds to the neat family portrait that is the Sun’s planetary system, and research into their origin and evolution has significantly improved our understanding of these worlds. With an emphasis on high-resolution spectroscopy, this talk will focus on secondary eclipse observations of the ultra-hot Jupiter, MASCARA-1b, in the near-infrared using the recently upgraded CRIRES+ spectrograph installed on the VLT. Cross-correlation analysis of MASCARA-1b reveals the presence of CO, H2O and Fe emission lines at high significance. While this technique is extremely efficient at detecting species, it is not sensitive to absolute line strengths, making it challenging to statistically compare the cross-correlation signals of various observations and model atmospheres. However, with recent developments in high-resolution Bayesian methods, these observations enable detailed atmospheric retrievals, allowing us to obtain quantitative information about the planet's composition, such as temperature structure and chemical abundances.

Atmospheres
composition, MASCARA1b, spectroscopy

Near-Infrared Transmission Spectroscopy with NIRISS: Disentangling Planetary and Stellar Features in the Era of JWST

Poster345Marylou Fournier Tondreau; University of Oxford

Poster AreaMon 08:00 - 17:50

Surface heterogeneities on active stars, such as starspots and faculae, can complicate the interpretation of transmission spectra and introduce spectral features that overlap those of exoplanetary atmospheres. The transit light curves of HAT-P-18b and WASP-52b, observed in the SOSS mode of JWST/NIRISS are affected by prominent spot-crossings. Our work on these data aimed to disentangle stellar and planetary atmosphere signals by including stellar heterogeneities in transit fits and atmospheric retrievals. Furthermore, we introduce new model considerations by fitting for the active regions’ surface gravities — a proxy for the effects of magnetic pressure. For the transit fits, we also use a new approach that simultaneously fits all spectrophotometric light curves using both wavelength-dependent and wavelength-independent parameters. We will report on our results for both planets, which show that stellar surface inhomogeneities and their effects on transmission spectra and atmospheric retrievals can be successfully modelled and constrained using SOSS data.

JWST Results
Exoplanetary atmospheres, Hot Jupiters, Transmission spectroscopy

NIRPS takes a look at Proxima

Poster435Alejandro Suárez Mascareño; Instituto de Astrofísica de Canarias

Poster AreaMon 08:00 - 17:50

The discovery of an Earth-like planet orbiting the habitable zone of our closest neighbor, Proxima Centauri (Gl 551), shook the planetary community. It showed that, given the right conditions, the nearest star to the Sun could host a habitable rocky planet. Since then, the star has been the focus of intensive campaigns with HARPS and ESPRESSO, aiming to confirm the presence of the planet and detect additional companions.We present the results of an observational campaign with NIRPS, the new RV-focused NIR spectrograph at the 3.6m telescope in La Silla. Our results confirm once again the presence of Proxima b and show that it is possible to achieve 1 m/s precision in the NIR. Taking advantage of the NIR spectral information we show we can measure differential changes in the effective temperature, that accurately track the stellar rotation.

RV and transits
Mdwarfs, NIR, NIRPS, Proxima

Observations and modelling of the upper atmospheres of the hottest ultra-hot Jupiters

Poster171Luca Fossati; Space Research Institute, Austrian Academy of Sciences

Poster AreaMon 08:00 - 17:50

Thanks to their large pressure scale heigths and typically bright host stars, ultra-hot Jupiters (UHJs) have become prime targets for atmospheric characterisation. These planets are believed to be subject to exceptionally large mass-loss rates, thus giving us the opportunity to study atmospheric escape in an extreme, and still poorly explored, regime. I will present the results of near-UV transmission spectroscopy observations of UHJs obtained with the CUTE SmallSat and of the modelling efforts carried out to constrain the atmospheric properties. I will further present detailed atmospheric modelling of UHJs fully accounting for non-local thermodynamical equilibrium effects. In particular, I will present comparisons of the modelling results with both low- and high-resolution transmission spectroscopy observations collected from space and ground, which clarify the source of the temperature inversion characterising the atmospheres of UHJs.

Atmospheres
Modelling and observations, Transmission spectroscopy, Ultrahot Jupiters

Observing the winds and structure of an ultra-hot Jupiter atmosphere with CRIRES+

Poster233David Cont; Universitäts-Sternwarte, Ludwig-Maximilians-Universität; CRIRES+ Consortium

Poster AreaMon 08:00 - 17:50

Although the spectroscopic characterisation of individual exoplanets has advanced in recent years, the atmospheres of key ultra-hot Jupiters (UHJs) still lack comprehensive investigations. These include WASP-178b, a UHJ orbiting the second hottest star with a transiting exoplanet known to date. Recently, we used CRIRES+ to observe the dayside emission spectrum of the planet in the K-band. We detect the emission lines of CO and H2O by using the cross-correlation technique. The CO and H2O signals show a significant Doppler-offset, indicating an inhomogeneous distribution of the two chemical species over the surface of the planet. Using a Bayesian retrieval framework, we find a strong atmospheric thermal inversion. In addition, we retrieve excess spectral line broadening, indicating the presence of fast super-rotation in the planetary atmosphere. Incorporating observations from additional wavelength bands into our analysis will further improve our understanding of the chemistry and dynamics in WASP-178b's atmosphere.

Atmospheres
Ultrahot Jupiters

On a treasure hunt: A spectral atlas of the ultra-hot Jupiter WASP-189 b with MAROON-X

Poster1370Bibiana Prinoth; Lund University

Poster AreaMon 08:00 - 17:50

The ultra-hot Jupiter WASP-189 b occupies an observational sweet spot. The brightness of the system, together with its geometry, allows for the investigation of resolved absorption lines. We observed two transits of WASP-189 b with the MAROON-X high-resolution spectrograph on Gemini-North and analysed the transmission spectrum, resulting in strong detections of atmospheric Ca+, Ba+, Na, Hα, Mg, Fe, and Fe+. Our analysis indicates that current models cannot fully describe the observed features, in particular the absorption of Fe+, necessitating different assumptions.Given the strong absorption of Ca+, observed consistently in every exposure, we fitted the Rossiter-McLaughlin effect in a time-resolved manner to obtain posterior distributions for planetary and stellar parameters.Our high signal-to-noise observations provide a benchmark dataset in the form of a spectral atlas for testing high-resolution retrieval and assumptions of atmospheric models.

Atmospheres
resolved lines, spectral atlas, ultrahot Jupiter

Panopticon: a machine learning model to detect transits in PLATO light curve

Poster465Hugo Vivien; Laboratoire d'Astrophysique de Marseille

Poster AreaMon 08:00 - 17:50

The detection of transits within light curves, especially those of small and long period planets, is a major challenge of the field.

We created a new Machine Learning Model, Panopticon, does not require any priori filtering of the data and does not relying on periodicity. We have successfully trained and evaluated this model on simulated PLATO light curves.

As it stands, the model is able to reliably detect (> 95%) planet larger than 2R⊕ , and already shows encouraging results regarding Earth analogs (∼ 30%). This is achieved with a False Alarm Rate of < 1%. Further work is aimed at improving small planets detection capabilities, and providing classification of the detected signal.

RV and transits
Machine Learning, Transit: detection

Peering above the clouds of the warm Neptune GJ 436b with CRIRES+

Poster184Natalie Grasser; Leiden University

Poster AreaMon 08:00 - 17:50

The warm Neptune-sized exoplanet GJ 436b is a prime example of an intermediate mass planet, which are among the most common, yet poorly characterized type of exoplanets. Their mean densities are compatible with a large variety of compositions, ranging from rocky cores with thick hydrogen envelopes to water-rich planets with steamy atmospheres. Low resolution HST spectra of these objects are often featureless, indicating either a high metallicity or a high cloud deck. Here we present our analysis of new CRIRES+ transit spectroscopy of GJ 436b, which could resolve this degeneracy due to being sensitive to features at low pressures above potential cloud decks. The high resolution spectra can also disentangle potential transit light source effects due to stellar heterogeneities from planet atmospheric signals.

Atmospheres
CRIRES+, Cross correlation, GJ 436b

Planet Formation at its Extremes – Giant Exoplanets around M-dwarf Star

Poster90Shubham Kanodia; Carnegie Institution for Science

Poster AreaMon 08:00 - 17:50

Giant (gaseous) exoplanets around M-dwarf stars (GEMS) represent an extreme of planet formation, attributed to the theorized difficulty in forming them. I will share preliminary results from the Searching for Giant Exoplanets around M-dwarf Stars survey, which includes a sample of a million M-dwarfs, and is expected to find 50–100 transiting GEMS while providing accurate estimates of their occurrence as a function of stellar mass. I will discuss how this sample has started to challenge our understanding of giant planet formation around low-mass stars and discuss exciting new trends in giant planet bulk properties across different samples. I will also present new results exploring gravitational instability as a means of rapid GEMS formation. Finally, I will discuss future prospects and the potential of this sample, including our JWST Cycle 2 program to study 7 GEMS, characterize their atmospheres, and determine their bulk metallicity.

RV and transits
Atmospheres, Demographics, M dwarf

Planet formation in stellar clusters via pebble accretion

Poster331Shuo Huang; Leiden Observatory

Poster AreaMon 08:00 - 17:50

Current exoplanet studies often overlook that most stars are born in the star cluster. However, the role of background massive stars is crucial across planet evolution, especially early formation. This paper investigates the differences in planet populations forming in star cluster environments through pebble accretion compared to those around isolated stars and tries to provide corresponding potential orientations for future observation. We synthesize planet populations since their growth and migration in the protoplanet disk. The gas and dust components are evolved using 1D hydrodynamical simulations under various star cluster environments. Our outcomes do show how stars and their surroundings affect planet types. Notably, a decrease in the occurrence rate of cold Jupiters and an excess of cold Earth, particularly around low-mass stars (<solar mass), are observed within the cluster setting. Future observation could focus on traits of planets around low-mass stars in wider orbits to understand their birth cluster origins.

Formation and evolution
accretion, accretion disks, planetdisk interactions, planets and satellites: formation, protoplanetary disks

Planet Populations Throughout The Galaxy: Insights from high-resolution galaxy formation simulations and planet population synthesis

Poster335Christopher Boettner; Kapteyn Astronomical Institute, University of Groningen

Poster AreaMon 08:00 - 17:50

Stellar populations differ widely across the Galaxy, affecting planet demographics. Our local neighbourhood is dominated by young, metal-rich stars, while the stellar halo and Galactic bulge host a large fraction of older, metal-poor stars. We study the impact of these variations on planet populations in different regions of the Galaxy by combining high-resolution galaxy formation simulations with planet population synthesis models. We construct a population model to estimate occurrence rates of different planet types, based on the New Generation Planet Population Synthesis by Emsenhuber et al., 2021. We apply this to a simulated Milky Way Analogue in the HESTIA galaxy formation simulation, and find that the overall planet populations in the thin disk are similar to those in the galactic bulge. The halo, however, is almost devoid of gas giants with masses >30 times that of Earth, due to the low solid mass in the protoplanetary disks around metal-poor stars.

Demographics & Architectures
Galaxy Formation and Evolution, Planet Population Synthesis

Planetary Eccentricity-Period distribution — differences between small- and giant-planets

Poster164Dolev Bashi; Tel-Aviv University

Poster AreaMon 08:00 - 17:50

The eccentricity of the exoplanet population, as revealed over the past three decades, differs markedly from the nearly circular orbits in our Solar System, hinting at unique attributes influenced by planetary mass and orbital period. In analyzing the planetary eccentricity-period (PEP) distribution, a clear distinction emerges between low- and high-mass exoplanets. Giant planets exhibit a monotonic upper envelope, similar to spectroscopic binaries, indicating tidal circularization, while low-mass planets display a flat eccentricity distribution almost unaffected by the orbital period, suggesting no circularization. In this talk, I will present the two PEP distributions and discuss their implications on our grasp of tidal effects and planetary system configurations and interactions with neighbouring planets.

Demographics & Architectures
methods: statistical, planets and satellites: dynamical evolution and st, planets and satellites: fundamental parameters

Polycyclic Aromatic Hydrocarbons in Exoplanet Atmospheres (Exploring Equilibrium Chemistry)

Poster318Dwaipayan Dubey; Ludwig Maximilans University of Munich

Poster AreaMon 08:00 - 17:50

Polycyclic aromatic hydrocarbons, largely known as PAHs, are widespread in the Universe and have been identified in a vast array of astronomical observations, from the interstellar medium to protoplanetary disks. They are likely to be associated with the chemical history of the Universe and the emergence of life on Earth. However, their abundance on exoplanets remains unknown. In the talk, I will be presenting the feasibility of PAH formation in the thermalized atmospheres of irradiated and non-irradiated hot Jupiters transiting around Sun-like stars and its dependency on other parameters (e.g. Carbon to Oxygen ratio, metallicity, effective planetary temperature, etc.) using a 1D self-consistent forward model. From the transmission and emission spectra of planets, we have constrained the best planetary candidates where PAH could have formed thermally. Finally, I will talk about the possible planet formation pathways that can lead to the formation of PAHs in planet atmospheres.

Habitability
Astrochemistry, Atmospheres, PAHs

Precision photometric follow-up of high-value TESS targets with MINERVA-Australis

Poster98Sakhee Bhure; University of Southern Queensland

Poster AreaMon 08:00 - 17:50

The Transiting Exoplanet Survey Satellite (TESS) has discovered thousands of planet candidates critical for studying the formation and evolution of planetary systems.

Precise ground-based photometry is crucial for confirming transits on stars with high rotation velocities or stellar activity that cannot be readily confirmed via radial velocity. Additionally, precise transit times and ephemerides are needed for small planets that are suitable targets for further analysis by large space telescopes such as JWST.

This project utilises the MINERVA-Australis array to do simultaneous photometry of a target with four separate 0.7m telescopes to achieve a fourfold reduction in scintillation. We aim to achieve a combined photometric precision that can facilitate the ground-based validation of even the smallest “high-value” TESS planets under 2 R_Earth, and down to 1.3 M_Earth planets orbiting M-dwarf stars. We present a demonstration of the array’s capabilities and aim to follow-up ~75 of these high-value TESS candidates.

RV and transits
groundbased followup, precision photometry, small planets

Preliminary result obtained through high-resolution cross-correlation spectroscopy of hot Jupiter, WASP-69b, using Gemini-S/IGRINS

Poster501Yeon-Ho Choi; Korea Astronomy and Space Science Institute

Poster AreaMon 08:00 - 17:50

The discovery of Jupiter-mass planets in very close orbits around stars has triggered debates on their formation scenarios. Planet formation theories suggest that these hot Jupiters are unlikely to have formed in situ at their present orbits and still their formation scenarios remain ambiguous. Chemical abundance of volatile molecules (H2O, CO, CO2) in hot Jupiter’s atmospheres might be able to differentiate its formation scenario. Here we present the preliminary result from high-resolution cross-correlation spectroscopy of WASP-69b a transiting hot Jupiter using the IR high-resolution spectrograph IGRINS on Gemini-South. We present the preliminary result of abundances of volatile molecules, including H2O and CO, in the atmosphere of this planet.

Atmospheres
Highresolution crosscorrelation spectroscopy, transit

Probing the Nature of Young Puffy Planets Through Theoretical Mass Constraints

Poster525Amalia Karalis; McGill University

Poster AreaMon 08:00 - 17:50

Discoveries of close-in young puffy planets raise the question of whether they are bonafide hot Jupiters or puffed-up Neptunes, potentially placing constraints on the formation location and timescale of hot Jupiters. Obtaining mass measurements for these planets is challenging due to stellar activity and noisy spectra. Therefore, we aim to provide independent theoretical constraints on the masses of these young planets based on their radii, incident fluxes, and ages, benchmarking to the planets of age <1 Gyr detected by K2 and TESS. Through a combination of interior structure models, considerations of photoevaporative mass loss, and empirical mass-metallicity trends, we present the range of possible masses for ~26 planets of age ~5-900 Myrs and radii ~3-16 Earth radii. Our results will address whether hot Jupiters can be emplaced close to their stars at young ages.

Formation and evolution
Starplanet connectionEnvelope evolution

Red Dwarf Upside-Down Cake: M Dwarf Evolution from a Brown Dwarf Perspective

Poster555Christopher Davis; University of California Santa Cruz

Poster AreaMon 08:00 - 17:50

M dwarfs make up 70% of all stars and host a myriad of exoplanets, making them some of the most important objects to characterize in astronomy. For several decades, M dwarf evolution models have had heritage in the methods of higher mass stars, but their molecule-dominated atmospheres and partially degenerate interiors share a greater kinship with sub-stellar objects. This has resulted in inaccurate constraints on the hydrogen-burning limit and the fundamental properties of M dwarfs and their exoplanets. However, recent state-of-the-art models on the molecule-rich atmospheres of these stars [1] using methods first used in brown dwarfs and ultra-hot Jupiters, and a reassessment of the dense interior equation of state [2], present a choice opportunity to close the gaps between models and observations of M dwarfs. We present our latest work, which integrates atmospheric boundary conditions from SPHINX [1] into MESA for self-consistent M dwarf evolution.

Star-planet interactions
M dwarfs, stellar evolution

Refractory abundances of the inner regions of protoplanetary disks.

Poster425Marbely Micolta; University of Michigan

Poster AreaMon 08:00 - 17:50

The inner regions of protoplanetary disks are nurseries for a wide diversity of exoplanets. Analysis of the emission lines of refractory elements allows us to trace their abundance in the inner gas disk and discern the footprints of planet formation by accessing the bulk of surviving material reaching the star. Our work focuses on Ca, one of the most refractory elements, tracing planetesimal and planet formation in the disks. We present a study of its abundance in the innermost regions of the disks of young low-mass stars in the Cha I, Lupus, and Ori OB1 star-forming regions. We use magnetospheric accretion models to estimate the Ca abundance, obtaining a wide range of Ca depletion. We find all disks with known structures show Ca depletion, but the opposite does not hold. We note an intriguing correlation with stellar mass, with the lowest Ca abundances found in stars with M<1 M⨀.

Formation and evolution
Refractory abundances

Searching for Atmospheric Outflow Variability in WASP-69b

Poster356W. Garrett Levine; Yale University

Poster AreaMon 08:00 - 17:50

XUV-driven photoevaporation is a leading hypothesis on the processes that sculpt the observed distribution of short-period planetary radii. In recent years, direct evidence of atmospheric escape has been detected via in-transit transmission of the metastable He triplet near 10830Å. Dozens of planets have been probed with this tracer, mostly as single-epoch snapshots. Since the stellar XUV that underlies planetary mass-loss is time-variable, outflows should respond to changes in the incident flux. Here, we report results from an ongoing longitudinal study to characterize WASP-69b’s atmospheric outflow. We obtained contemporaneous metastable He data from Palomar/WIRC along with X-ray and mid-UV data from the Swift Observatory. Together, these data lead to a comprehensive characterization of WASP-69b’s hydrodynamical state in the epoch of observation. By comparison to archival metastable He data and archival high-energy data from XMM-Newton, we assess the time variability of WASP-69b’s mass-loss rate on timescales commensurate with stellar activity cycles.

Atmospheres
MassLoss, Metastable He

Searching for liquid surface water on Earth-like exoplanets with spectropolarimetry

Poster132Aurora Cagnoni, Delft University of Technology, Politecnico di Milano

Poster AreaMon 08:00 - 17:50

The discovery of liquid water on an exoplanet would be a milestone in the search for extraterrestrial life, as liquid water is considered to be a prerequisite for life as we know it. The design of future telescopes that could possibly detect liquid water on exoplanets rely on numerical simulations of reflected starlight by exoplanet models.In this talk, we present the simulated reflected signal of Earth-like exoplanets with realistic (rough) ocean surfaces, for both the total and the polarized light. We will discuss the unique ocean signatures in the polarization spectra from the visible to the near-infrared and in the planetary phase curves (Trees and Stam, 2019,2022). We will explain our ongoing efforts to verify our model predictions with observations of the Earth as an exoplanet, through Earth-shine measurements via the Moon with the VLT, and from the Moon directly with Moonshot, the planned Moon mission of TU Delft.

Habitability
Earthlike exoplanets, oceans, polarimetry, radiative transfer

Searching For Transiting Planets around Red Clump Stars: Constraining the Occurrence Rate of Close-In Planets

Poster107Victoria Bonidie; University of Pittsburgh

Poster AreaMon 08:00 - 17:50

Stars are expected to engulf close-in planets as they ascend the red giant branch, however, the recent discoveries of Jovian-sized planets around a white dwarf with a 1.4-day orbital period by Vanderburg et al. (2020), and around a red clump star with a 93.3-day orbital period by Hon et al. (2023) complicates this idea. To further investigate this question, we perform a transit survey using Kepler light curves of 2,452 APOKASC-identified red clump (post-RGB) stars in order to constrain the upper limit of planetary occurrence around red clump stars with orbital periods P ≤ 20 days. Our results will have strong implications for the survival of planets engulfed during the RGB phase of their host.

RV and transits
planet occurrence planetstar interactions, red clump

Space environment and ohmic heating of the TRAPPIST-1 exoplanets due to interplanetary coronal mass ejections

Poster253Filip Elekes; University of Cologne

Poster AreaMon 08:00 - 17:50

The Trappist-1 system is a remarkable star system with 7 terrestrial exoplanets. The central M-dwarf star is a flaring star, which likely exerts a large impact on the space weather surrounding the planets. The effect of flare-associated coronal mass ejections (CMEs) on the space environment of exoplanets is an important aspect that can strongly influence atmospheres, the planets interior energy budget, their magnetospheres, if any, and ultimately the habitability of such planets. We perform magnetohydrodynamic simulations in which we study the interaction of interplanetary CMEs with the space environment of the Trappist-1 exoplanets. We study the interaction of magnetized and non-magnetized planets with density-pulse and fluxrope CMEs, the planetary energy budget during such events, and effects on interior heating of those planets. We examine the effects of atmospheres on the CME-planet interaction and characterize magnetic variability at the planetary surfaces which ultimately controls CME energy dissipation within the planetary interior.

Star-planet interactions
Interplanetary coronal mass ejections, Space weather, Starplanet interactions

Spectral follow-up of astrometrically selected planet host candidates using Apache Point Observatory.

Poster383Anne Peck; New Mexico State University

Poster AreaMon 08:00 - 17:50

Accelerating stars potentially host planets. If they are young, those planets could be directly imageable. By combiningGaia and Hipparcos measurements, we have identified stars with accelerations consistent with substellar companions at intermediate separations (5-20AU) but also unresolved short-period stellar binaries. We use spectra taken with the echelle spectrograph, ARCES, on the 3.5-meter telescope at Apache Point Observatory to determine each star’s suitability for direct imaging. We use ARCES data to conduct radial velocity monitoring of the sample to screen for stellar binaries. Using a Bayesian approach, we derive ages from rotation rates extracted from TESS light curves and from R’HK and lithium equivalent widths measured from ARCES spectra. Screening our sample for stellar binaries and identifying the youngest stars are key steps in generating a prioritized list of targets for direct imaging and increasing the number of directly imaged exoplanets. We present preliminary results from this ongoing survey.

Direct Imaging and Interferometry
Accelerating Stars, Astrometry, Bayesian

Stellar activity and planetary signals investigated through TOI1727, a solar-like star with a rocky planet.

Poster466Alix Freckelton; University of Birmingham

Poster AreaMon 08:00 - 17:50

With the first light of instruments capable of detecting Earth-Sun analogues dawning in the next few years, a fundamental understanding of how solar-like stars impact the signals of small, rocky planets is crucial. I present TOI-1727, a system consisting of a sun-like star and a transiting sub-neptune planet on a 3.66 day orbit. Signals arising from stellar activity in TESS photometry produced ambiguity in the planet's orbital period. To clarify this, I used HARPS-N radial velocities, together with two sectors of TESS data. Due to the amplitude of stellar activity signals being significantly larger than the planetary signal, a multi-dimensional gaussian process fit was performed, implemented using the python package pyaneti. Such drastic overshadowing of planetary signatures by their host stars will be commonplace when the field progresses towards Earth-Sun analogue systems. This investigation thus represents a cornerstone in the development of our understanding of stellar activity.

RV and transits
stellar activity, transit

Stellar echoes: searching for the reflected light of exoplanets

Poster312Sophia Vaughan; University of Oxford

Poster AreaMon 08:00 - 17:50

It will soon be possible to search for biosignatures in the atmospheres of the nearest Earth-sized, habitable zone exoplanets. While transit spectroscopy is an exciting avenue for this work, these exoplanets are unlikely to transit. To study non-transiting worlds and gain additional information on the transiting ones, we can look at their reflected light. I will report on our recent observations untangling the mystery of the unusually reflective LTT9779 b using High Resolution Cross-Correlation Spectroscopy with the world's largest optical telescope – the Very Large Telescope with ESPRESSO in 4UT mode. This planet’s reflection properties can illuminate its survival in the hot Neptune photo-evaporation desert. I will also show work on simulating future coronographic instruments for characterising Earth-like planets. For HARMONI/ELT, I will show the feasibility of characterising Proxima b and for the Habitable Worlds Observatory, I will demonstrate how the detection of liquid water via rainbows could be achieved.

Atmospheres
Atmospheres, Future missions/ instrumentation

Study of characteristics of a stellar catalogue suitable for the PLATO Fine Guidance System

Poster183Samuel Bowling; Institute of Planetary Research, German Aerospace Center (DLR)

Poster AreaMon 08:00 - 17:50

PLATO (PLAnetary Transits and Oscillations of stars) is an exoplanet observing satellite currently in development by ESA. The main science goal of PLATO is to detect and characterize extrasolar planets, including terrestrial planets in the habitable zone (HZ) of their host stars. Detecting rocky planets in the HZ requires high photometric stability, which depends on the telescope’s pointing performance. PLATO’s pointing performance is managed by the Fine Guidance System (FGS), which utilizes a catalog of guide stars to determine the spacecraft’s attitude. Guide stars used by the FGS must fit several requirements regarding their magnitude, environment, and photometric variability. In this work, we study the impact of stellar variability on the design of the guide star catalog for PLATO.

Future missions/instrumentation
Instrumentation, Photometry, Stellar variability

Surveying hot Jupiter atmospheres with Keck/KPIC

Poster384Luke Finnerty; UCLA

Poster AreaMon 08:00 - 17:50

As exoplanet science moves towards detailed characterization of individual planets, ground-based high-resolution spectroscopy with ultra-stable line-spread functions, as provided by Keck/KPIC, is a critical tool to complement transmission spectroscopy from JWST. High-resolution emission spectroscopy of hot Jupiters is less sensitive to clouds and hazes than transmission techniques and more sensitive to the pressure-temperature profile and atmospheric winds. High-resolution observations provide unambiguous molecular identifications and precise relative abundance measurements, including isotopologue ratios, offering insight into non-equilibrium chemistry, bulk composition, and formation pathways. We present initial results from our ongoing Keck/KPIC survey of hot Jupiter atmospheres, with 10 detections to-date. We have obtained constraints on the dayside abundances of molecular species including H2O, CO, OH, and CH4 for WASP-33 b, WASP-189b, KELT-20b, and HD 189733 b. Ongoing improvements in atmospheric retrieval pipelines are also enabling robust measurements of wind speeds for these targets that will test global circulation models.

Atmospheres
composition, highresolution spectroscopy, infrared

Temperate exoplanets: golden targets for linking observations and modeling

Poster468Solène Ulmer-Moll; Space Research and Planetary Sciences, Physics Institute, University of Bern

Poster AreaMon 08:00 - 17:50

Most detected transiting planets have orbits which would fit within that of Mercury. This host star proximity means that the properties of these planets undergo significant changes due to stellar irradiation and interactions. In contrast, temperate planets with longer orbital periods are less affected, offering crucial insights into their formation and migration histories. Characterizing transiting temperate planets is a key missing piece in the exoplanet puzzle. In this talk, I report the detection and characterization of three new transiting temperate Jupiters with orbital periods larger than 100 days, thanks to a three-year ground and space-based photometric and radial velocity survey. I infer the metal enrichment of the newly discovered temperate giants and explore their influence on the mass-metallicity correlation of giant planets. This work is also a stepping stone for PLATO as the follow up of single transit candidates will be key in order to detect transiting Earth analogs.

RV and transits
Characterization, Gas giants

The coupled impact of atmospheric dynamics and cloud microphysics on WASP-43b and WASP-121b

Poster289Emeline Fromont; University of Maryland

Poster AreaMon 08:00 - 17:50

Hot gas giant planets are currently the best observational targets to study clouds in exoplanet atmospheres. Observations have reported westward visible phase curve offsets, weak absorption features, and nightside temperatures that remain constant with increasing instellation, which may together be explained by the presence of clouds. Additionally, there is a need for more accurate models to track the formation and transport of clouds as well as their radiative feedback on atmospheric circulation and dynamics. In this work, we consider a series of increasingly complex models of WASP-43b and WASP-121b by conducting cloudless 3D general circulation models with the MITgcm, feeding the results into a series of 1D CARMA models simulating mineral cloud microphysics, and calculating resulting synthetic spectra with PICASO. We discuss implications for the interpretation of JWST/MIRI and JWST/NIRSpec observations of WASP-43b and WASP-121b, respectively.

Atmospheres
General Circulation Model, Hot Jupiter, Microphysics

The diversity of Neptune-sized Exoplanets

Poster561Luigi Mancini; University of Rome "Tor Vergata"

Poster AreaMon 08:00 - 17:50

Neptune-sized Exoplanets exhibit a wide diversity of masses, their bulk density being a key parameter that can provide insights into whether these planets are predominantly composed of volatile materials or denser substances such as water or rocky materials. Such information is fundamental for understanding their formation and evolution, especially for those that lie in the hot-Neptune "desert" where the vicinity with their parent stars can induce atmospheric escape processes. We present the results of a RV monitoring of several Neptune-sized TOIs performed with the HARPS-N spectrograph. We highlight the recent discovery of the Neptune-sized TOI-1853b, which has a density of roughly six times that of Neptune and represents a puzzle for conventional theories of planetary formation and evolution as well as an emblematic case of composition degeneracy. Such an uncanny discovery tell us that the parameter space of Neptune-sized planets can still hide surprises and needs to be systematically investigated.

RV and transits
Neptunesized exoplanets

The dynamics of the TRAPPIST-1 system in the context of its formation

Poster350Shuo Huang; Leiden Observatory

Poster AreaMon 08:00 - 17:50

TRAPPIST-1 is an M-dwarf, which harbors a system of seven Earth-sized planets. Such planetary similarity indicates their same formation origin. Previous works have outlined a pebble-driven formation scenario where planets of similar composition form sequentially at the water snowline. Here, we investigate whether this sequential formation model is indeed capable of producing the present-day dynamical configuration. We carry out N-body simulations, accounting for type-I migration featuring a migration barrier located at the disc’s inner edge. Due to migration, planets naturally form a chain of first-order resonances. But we find that planets b and c must have marched into the gas-free cavity before the disc dispersed to explain the observed architecture. We outline how the insights obtained in this work can be applied to aid the understanding of other compact resonant planet systems.

Formation and evolution
planet–disc interactions, planets and satellites: dynamical evolution and s, planets and satellites: formation, protoplanetary discs

The Effects of Kinematic MHD on Eccentric Hot/Ultrahot Jupiter GCMs

Poster438Willow Houck; University of Maryland

Poster AreaMon 08:00 - 17:50

We are now at the precipice of characterizing the three-dimensional atmospheric dynamics of eccentric hot-Jupiters in detail. In this work, we study the active magnetic drag effects that vary in strength as the local temperature is affected by the changing incoming stellar flux and their impact on the resulting three-dimensional atmospheric circulation. We use a 3D atmospheric model with a kinematic MHD approach, which calculates a drag timescale for each grid point to simulate the effect of Lorentz forces. This method allows for changes in magnetic drag timescales of over 10 orders of magnitude for a single pressure level from the day to the night side. We compare magnetic and non-magnetic models to understand the role magnetism has on wind and temperature structures for eccentric planets. We post-process GCMs to simulate JWST phase curves for both magnetized and non-magnetized cases and determine whether magnetism has detectable consequences for eccentric hot-Jupiters.

Atmospheres
Atmospheric GCMs, Phase Curves, Ultra Hot Jupiters

The HUSTLE program: Unveiling the UV-optical spectrum of Hot Gas Giants with Hubble

Poster276Carlos Gascón; Center for Astrophysics | Harvard & Smithsonian

Poster AreaMon 08:00 - 17:50

With numerous observations in the near to mid- infrared, our growing understanding of exoplanet atmospheres has begun to reveal a complex but fascinating picture. Nonetheless, without robust UV and optical observations that probe beyond the reach of JWST, this picture still remains incomplete. Here we present the Hubble Ultraviolet-optical Survey of Transiting Legacy Exoplanets (HUSTLE) program; aimed at exploring the UV-optical spectra of a rich sample of 13 hot gas giants using Hubble’s WFC3/UVIS G280 grism. We show the 200-800 nm transmission spectra of several of the observed targets, and combine these results with previous observations to create a sample of UV-optical spectra of exoplanets with Teq=1500-2500K and Mp=0.5-1.5 Mj. As a result, we start to draw a coherent picture in which we relate system parameters to the unique atmospheric properties (e.g., aerosol composition, presence of unexplored absorbers, or enhanced scattering) revealed in the near-UV.

Atmospheres
Hot Gas Giants, UltravioletopticalHubble Space Telescope

The Impact of Cometary ‘impacts’ on the Chemistry, Climate, and Observations of Earth-like Exoplanetary Atmospheres

Poster244Felix Sainsbury-Martinez; University of Leeds

Poster AreaMon 08:00 - 17:50

Impacts of icy and rocky bodies have shaped the resulting composition of solar-system objects, and the habitability of the Earth. Such impacts are also highly likely to occur on exoplanets and may indeed be a key mechanism for the delivery of water to potentially habitable exoplanets. We couple an impact model, which includes both thermal ablation and pressure-driven breakup, with the 3D Earth-system model WACCM/CESM. We use this model to explore the short and long term effects associated with a massive, pure-water-ice, impact. This includes investigating the advection of water and heat (associated with the impact) away from the impact site, the changes to local and global chemistry linked with this deposited water and heat. We also investigate the potential observability of such an impact with, for example, JWST.

Atmospheres
Methods: numerical, Planets and satellites: atmospheres, Planets and satellites: composition, Planets and satellites: terrestrial planets

The impact of convection on the climate of a tidally locked planet in stretched-mesh simulations

Poster519Denis Sergeev; University of Exeter

Poster AreaMon 08:00 - 17:50

Convective processes are crucial to shaping exoplanetary atmospheres but are computationally expensive to simulate directly. A novel technique of simulating moist convection is to use a 3D general circulation model (GCM) with a global stretched mesh. It allows us to locally refine the model resolution and resolve deep convection without relying on parameterizations. We explore the impact of mesh stretching on the climate of TRAPPIST-1e, a confirmed rocky exoplanet and a primary candidate for atmospheric characterization. We show that resolved convection leads to changes in cloud cover, albedo, precipitation and water vapor distribution on a planetary scale. Our methodology opens an exciting and computationally feasible avenue for improving our understanding of 3D mixing in exoplanetary atmospheres.

Atmospheres
Clouds, Convection, General Circulation Models (GCMs)

The Influence of Photometry on Deconfusion of Directly Imaged Multi-Planet Systems

Poster449Samantha Hasler; Massachusetts Institute of Technology

Poster AreaMon 08:00 - 17:50

Future direct imaging missions, like the Roman Space Telescope and the Habitable Worlds Observatory, will be capable of directly imaging the reflected light from exoplanets. However, these missions are likely to encounter a “confusion” problem when imaging multi-planet systems. Previous work has shown that planets in multi-planet systems can be “confused” in direct images taken over multiple epochs, due to lack of prior knowledge about planets’ orbital parameters or characteristics.

We must be able to differentiate planets in multi-planet systems in order to determine their orbital parameters, characterize their atmospheres, and estimate the potential for habitability. In this work, we address the confusion problem by introducing the inclusion of photometric properties to a “deconfusion” algorithm, which uses intensity variation with orbital phase to improve differentiation between orbit options returned by the deconfuser. We will report results of our Monte Carlo investigation using both astrometric (positional) and photometric information.

Direct Imaging and Interferometry
direct imaging, orbit determination

The interplay between pebble and planetesimal accretion in giant planet formation

Poster447Andrin Kessler; University of Bern

Poster AreaMon 08:00 - 17:50

The accretion of roughly kilometre-sized planetesimals or of millimetre- to centimetre-sized pebbles are typically discussed seperately as the main core accretion mechanisms in planet formation. We investigate the consequences of a combined pebble and planetesimal accretion model for the formation of giant planets using a single-planet population synthesis approach [1].We find that it is difficult to form giant planets from the accretion of pebbles and planetesimals, whereas both mechanisms individually are able to form giants in suitable disks. We identify the remaining accretion of planetesimals and the consequential envelope heating after the stop of pebble accretion to be crucial for the formation pathway of a growing planet. We conclude that a combination of enhanced inward orbital migration and delayed runaway gas accretion strongly suppresses the formation of giants in disks containing both pebbles and planetesimals.

Formation and evolution
Giant planet formation, Pebble accretion, Planetary migration, Population synthesis

The K2 & TESS Synergy: Uniting NASA’s Planet Hunters

Poster442Erica Thygesen; Michigan State University

Poster AreaMon 08:00 - 17:50

The early success of JWST provides an exceptional opportunity to study the atmospheres of exoplanets with unprecedented detail. However, most (>80%) confirmed transiting exoplanets will not beaccessibleduring the mission’s lifetime. This widespread problem is due mostly to ephemeris degradation: uncertainties on transit time and period compound over time, which can culminate in predicted future transits being off by hours to days. With this in mind, I am leading the K2 & TESS Synergy, aneffort to reanalyse all ~300 systems discovered by NASA's K2 mission with new observations from TESS. I will discuss ourreanalysis of 26 systems from the TESS primary mission, ourcurrent work addressingthe top 50 targets for atmospheric follow-up, and our plans to complete the catalogue. Efforts like this will ensure the accessibility of transiting planets for future characterisation while leading to a self-consistent catalogue of stellar and planetary parameters for population studies.

RV and transits
Catalogues, Ephemerides

The Limiting Factors: Extending our Observational Capabilities to Probe the Atmosphere of KELT-9b

Poster281Nicholas Borsato; Macquarie University

Poster AreaMon 08:00 - 17:50

Ultra-hot Jupiters, exemplified by KELT-9b (4000 K, V ~ 7.6 host star), have been crucial in advancing exoplanet observation techniques. Their significant transmission depths and bright emission spectra permit the detection of atmospheric features using modest telescopes. By combining 13 high-resolution transit observations, employing cross-correlation and alias-regression to enhance sensitivity, we identified new atomic and ionised species in KELT-9b's atmosphere, including Ca I, Cr I, Ni I, Sr II, Tb II, Ti I, V I, and Ba II. Our results demonstrate that smaller (2 m) telescopes can replicate results from the HARPS-N spectrograph for targets down to V ~ 10.5, given repeated observations. Additionally, our observations with larger (~10 m) telescopes allow us to resolve individual metal absorption lines in the planet’s atmosphere, enabling direct spectrum extraction without reliance on cross-correlation. This research pushes the boundaries of current observational methods and illuminates a path for future atmospheric exploration of exoplanets.

Atmospheres
Crosscorrelation, HighResolution Transit Observations, Ultrahot Jupiters

The Not-So Dramatic Effect of Advective Flows on Gas Accretion

Poster457Vincent Savignac; McGill University

Poster AreaMon 08:00 - 17:50

Super-Earths and mini-Neptunes are the most common types of exoplanets discovered, yet the scenarios behind their formation are still debated. Standard core accretion models in gas-rich environment find that typical mini-Neptune mass planets would blow up into Jupiters before the underlying disk gas dissipates away. Using one-dimensional structure models with realistic equation of state (EOS) and opacities, we reevaluate whether the injection of disk entropy into gaseous envelopes can halt runaway accretion. While entropy advection can indeed stop runaway, we find that it is insufficient to explain the measured masses and radii of close-in mini-Neptunes. Our findings highlight the importance of realistic treatment of EOS and opacities, allowing for a strategy to disambiguate between different formation conditions of gas-poor planets past 1 AU using future instruments such as the Nancy Grace Roman Space Telescope.

Formation and evolution
Atmospheric recycling, Gas accretion, superEarths and miniNeptunes

The occurrence rates of young, Neptune-sized planets with ages less than 200 Myr

Poster10Sydney Vach; University of Southern Queensland

Poster AreaMon 08:00 - 17:50

In this talk, we will present our occurrence rates of short-period, young planets (<200 Myr). We conducted a holistic occurrence rate study using both Full Frame Images (FFIs) and the 2 minute cadence observations from NASA's Transiting Exoplanet Survey Satellite (TESS), sampling over 8000 total stars known to reside in young clusters or associations. We find evidence for both period and radius evolution of planets over the first hundred million years.Our occurrence rates test the contraction, photoevaporation, and potentially migration processes that all planets undergo early in their lives. This is the critical timescale by which the intense XUV irradiation from young, active host stars is thought to strip planets’ primordial atmospheres. Comparing the population of planets around young stars against that of their mature counterparts is one avenue to time stamp these processes as they occur.

Demographics & Architectures
planet evolution, Young Planets

The origin and evolution of wide Jupiter Mass Binary Objects in young stellar clusters

Poster1648Erwan Hochart; Leiden Observatory, University of Leiden

Poster AreaMon 08:00 - 17:50

Using direct N-body integrations, we examine the origin and survival of freely-floating Jupiter-mass Binary Objects (JuMBOs) in the Trapezium cluster. Four models are discussed: SPP, where selected stars have two outer orbiting Jupiter-mass planets; SPM, where selected stars are orbited by Jupiter-mass planet-moon pairs; ISF, where JuMBOs form in-situ with the stars, and F F C, where we introduce a population of free-floating single Jupiter-mass objects, but no initialised binaries. Models F F C and SPP fail to produce enough JuMBOs. Models SPM produces sufficient free-floaters and JuMBOs, but requires unusually wide orbits for the planet-moon system around the star. Model ISF best reproduces observations if they formed in pairs and as free-floaters when assuming a smooth(Plummer)stellar density profile with virial radius of ∼ 0.5 pc. A fractal (fractal dimension 1.6) stellar density distribution also works, but requires recent formations(≳ 0.2 Myr) or a high (≳ 50%) initial binary fraction.

Formation and evolution
Earth and Planetary Astrophysics, Jupitermass Binary Objects (JuMBOs), Nbody Simulation

The phases of an ultra-hot gas giant from the optical to the mid-infrared

Poster471Adrien Deline; University of Geneva

Poster AreaMon 08:00 - 17:50

WASP-18 b belongs to the realm of ultra-hot Jupiters (UHJs): gas giant planets that orbit very close to hot and massive early-type stars. These objects undergo extreme conditions with dayside temperatures that can reach that of the coldest stars. Their atmospheric composition is dominated by ions and dissociated molecules, which inhibit global circulation leading to inefficient heat redistribution and strong day-to-night temperature gradients. Such conditions create large thermal emission contrasts between dayside and nightside, making UHJs particularly amenable to atmosphere mapping with observations at various phase angles.

Our work covers the joint analysis of phase-curve observations of WASP-18 b with several space-based telescopes, namely CHEOPS, TESS, HST and SPITZER, spanning a spectral range from visible to mid-infrared. We discuss key atmospheric properties including composition, vertical T-P structure, magnetic drag, and variability. Our study also explores how JWST observations (Coulombe et al. 2023) compares with and impacts our results.

Atmospheres
Phase curve, WASP18 b

The Progress of East Asian Planet Search Network

Poster360Huan-Yu Teng; National Astronomical Observatories, Chinese Academy of Sciences

Poster AreaMon 08:00 - 17:50

East Asian Planet Search Network (EAPS-Net) surveys late-G (including early-K) giant stars with precise radial velocities, aiming to search for planets around intermediate-mass stars in their evolved stages. The EAPS-Net began 20 years ago, with 48 exoplanetary systems discovered by telescopes in East Asia. In this presentation, we report the latest discoveries from the EAPS-Net and statistical information from planet surveys around evolved stars.

RV and transits
Evolved stars, Giant planets, Radial velocity

The quest of life-as-we-know-it outside the Solar system: the time-evolution of the ultraviolet habitable zone

Poster520Riccardo Spinelli; INAF

Poster AreaMon 08:00 - 17:50

The majority of discovered rocky exoplanets in the habitable zone (HZ) orbits around old M stars, but it is unclear if the high-energy emission of these stars provides a suitable environment for the origin of life. According to Spinelli el al. 2023, the current Near Ultraviolet (NUV) luminosity of M stars hosting HZ exoplanets is too low to trigger RNA precursors formation on them. By combining Swift-UV/Optical and GALEX data, we investigate the temporal evolution of their ultraviolet habitable zone (UHZ), the annular region around a star in which an exoplanet could experience a suitable ultraviolet environment for the presence and emergence of life, and its intersection with the HZ around K and M stars. I will show the temporal evolution of radial extension of the UHZ and its intersection with the classical HZ for different stellar types, focusing also on the curious case of Proxima Cen.

Habitability
Abiogenesis, Astrobiology, Starplanet interaction, Ultraviolet

The Reanalysis and Recharacterization of 1RXS + 3127 B’s Spectral Type

Poster108Phoenix-Avery Sarian; The Ohio State University

Poster AreaMon 08:00 - 17:50

Brown dwarf atmospheres can provide insight into their formation history, circulation processes, and other key physical properties. Across different spectral types, these atmospheres display a wide range of features which can be used for classification. Spectral typing is a vital step towards understanding what to expect and putting the individual brown dwarf into context with other objects. For early L-dwarfs, the temperature can be correlated back to its spectral type. We focus on refining and reassessing the spectral type of the young, low surface gravity, intermediate-mass brown dwarf 1RXS J2351+3127 B, which was previously classified as an L0 over a decade ago. We compare near-infrared spectra of this object to other brown dwarfs in the updated SpeX Prism Spectral Library to constrain its spectral type. We will use our new classification for future studies of this brown dwarf’s atmospheric composition as a step towards inferring its formation pathway.

Atmospheres
spectroscopyatmospheric characterization

The search for induced stellar flares using TESS

Poster279Tansu Daylan; Washington University

Poster AreaMon 08:00 - 17:50

The detection of exoplanetary magnetic fields is an essential goal for the continued characterization and contextualization of exoplanets. In particular, an orbiting exoplanet with a magnetosphere can induce flares on its host via magnetic reconnection. We conduct a comprehensive search for induced flares in multi-cadence TESS data in the first five years of the mission, using Bayesian evidence to vet underresolved flare candidates. Specifically, we estimate the flare frequency distribution by cataloging flares from low-mass M dwarfs with confirmed or candidate planets. We discuss candidate targets potentially manifesting star-planet interactions based on elevated flaring activity correlated with arguments of periastron and Alfven-surface crossings. Continued long-term monitoring of flaring stars by TESS and the upcoming ULTRASAT mission will yield complementary tests for the accumulating evidence for the existence of planetary magnetospheres based on radio observations of the Low-Frequency Array (LOFAR) and UV observations of the Hubble Space Telescope (HST).

Star-planet interactions
Induced stellar flare, magnetic reconnection, magnetosphere

The SISTINE Sounding Rocket: The high-energy radiation environment in Sun-like binary systems

Poster343Patrick Behr; University of Colorado, Boulder

Poster AreaMon 08:00 - 17:50

Approximately two-thirds of the stars listed in the NASA ExEP Mission Star List for the Habitable Worlds Observatory (HWO) are multiple star systems—it is therefore crucial to consider the effects of stellar companions on exoplanet atmospheres. In July 2022, the third flight of the Suborbital Imaging Spectrograph for Transition Region Irradiance of Nearby Exoplanets (SISTINE) observed α Centauri AB, fully resolving both stars with moderate spectral resolution (R~1500) over a broad ultraviolet bandpass (1000-1565 Å). We combine data from SISTINE with archival X-ray, UV, and visible data to create full X-ray-infrared spectra of a prototypical sun-like binary star system. Combing our spectra with previous knowledge of α Centauri, we compute lifetime-integrated high-energy radiation and potential temperature-pressure profiles at the extremes of stellar separation and activity cycles. These results probe a representative range of potential atmospheric responses in the binary environments to be explored with HWO.

Star-planet interactions
binary system, farultraviolet, spectroscopy

The space weather around the exoplanet GJ 436 b

Poster192Stefano Bellotti; Leiden Observatory

Poster AreaMon 08:00 - 17:50

Exoplanet-hosting stars dictate the space environment in which planets are embedded, affecting their atmospheric evolution. The M dwarf star GJ436 hosts a warm-Neptune that experiences a substantial atmospheric loss. This was modelled as a comet-like trail of hydrogen atoms shaped by the interactions with the wind of the host star. We reconstructed the large-scale magnetic field of GJ436, obtaining a slightly-tilted dipolar configuration. We then used such information as a boundary condition to model GJ436's magnetised wind, finding that the planet orbits through the stellar wind in sub-Alfvénic motion. This allows magnetohydrodynamic waves and particles released in reconnection events to travel along the magnetic field lines toward the star, and power the anomalous ultraviolet flare distribution observed in the system. We derived the power released by stellar wind-planet interactions to be 1022-1023 erg/s, which is consistent with the upper limit of 1026 erg/s derived from ultraviolet lines.

Star-planet interactions
star: outflows, stars: magnetic field, stars: winds, techniques: polarimetric

The spin-orbit angle distribution of close-in exoplanets under the lens of tides

Poster485Omar Attia; University of Geneva

Poster AreaMon 08:00 - 17:50

The distribution of close-in exoplanets is sculpted by a complex interplay between atmospheric and dynamical processes, which notably manfests itself by a "desert" of hot Neptunes. The past history of the planets populating its rim can be accessed through the study of a particularly powerful observational marker, the spin-orbit angle, or obliquity. Our results reveal a striking pile-up of highly misaligned orbits, favoring high-eccentricity migration to explain such orbits for several warm Neptunes and supporting the role of late migration in shaping the desert. By devising a broader statistical context, we connect the distribution of obliquities to the intensity of tidal interactions between close-in planets and their host stars. Our comprehensive statistical analysis corroborates the strong link between close-in orbital architectures and tides, and further highlights that planets bordering the desert are particularly affected by disruptive dynamical processes misaligning their orbits, challenging the classical picture of planet formation and evolution.

Demographics & Architectures
obliquity, spinorbit, statistics

The stable atmospheric dynamics of hot Jupiters

Poster280Thaddeus Komacek; University of Maryland

Poster AreaMon 08:00 - 17:50

Over the past two decades, a coherent picture has emerged for the atmospheric dynamics of hot Jupiters from both three-dimensional general circulation models (GCMs) and observations. The standard model of hot Jupiter atmospheric circulation consists of a strong superrotating equatorial jet driven by a planetary-scale standing wave pattern triggered by day-to-night irradiation contrasts. This circulation pattern is relatively stable, with time-variability due to dynamics potentially detectable yet only at the few percent level in temperature. Conversely, current models for the atmospheric dynamics of sub-Neptunes and rocky planets often display hysteresis and time-variability, the former of which may be especially common at the boundaries between dynamical regimes. In this work, I explore the extent to which hot Jupiter circulation is independent of initial temperature and wind conditions. I find that the resulting dynamics is ubiquitously insensitive to the initial conditions, implying that the current paradigm of hot Jupiter circulation is robust.

Atmospheres
Hot Jupiters

The stormy coupled chemistry and clouds of directly imaged exoplanets and brown dwarfs

Poster100Elspeth Lee; University of Bern

Poster AreaMon 08:00 - 17:50

Early JWST observations have shown a tantilising glimpse into the atmosphric properties of companion brown dwarf and exoplanets. With initial observtional performance better than expected, we now have an oppertunity to characterise Solar System giant planet anaolgues, and potentially smaller Neptune sized planets for the first time. In this talk, I present 3D GCM simulations of these enigmatic planets, for the first time, coupling complex atmospheric kinetic chemistry and cloud formation in a dynamical fashion with feedback onto the underlaying atmosphere. I show that the chemical structure and clouds are inherently linked together, producing stormy features that affect local chemical compositions, and that we can expect signicant variability in chemical and cloud signatures in their spectral features. Lastly, I look at some of the expect variation we might see in the climatatic patterns of these objects and outlook for the future of deatiled forward models on these objects.

Direct Imaging and Interferometry
Atmospheres

The Tianlin Mission: a 6m class UV-to-NIR Space Telescope for Habitable Worlds and Extraterrestrial Lifes

Poster458Wei Wang; National Astronomical Observatories, Chinese Academy of Sciences

Poster AreaMon 08:00 - 17:50

The transit planet survey missions including TESS and PLATO will detect ~103 small to medium-sized planets, including ~102 habitable terrestrial rocky planets. To conduct atmospheric study of them, large aperature space telescopes are highly demaned. In the meanwhile, astronomy in UV has been largely left behind due to the lack of powerful instrument in the past and upcoming 20 years. China is therefore funding a concept study of a 6-m class UV-to-NIR space telescope named Tianlin (or HABITATS) that aims to start its operation within the next 15 years and last for 10+ years. Tianlin will be dedicated for the characterization of nearby habitable zone rocky planets and systematic study of exoplanets. Tianlin will provide amazing data for other astrophysical areas as well. We briefly describe the concept study of this mission and propose a baseline setup of the telescope and instrumental parameters based on our preliminary simulation.

Future missions/instrumentation
coronagraph, exoplanets, space telescope; habitable worlds; biosignature

Three close-in planets with a long-period Saturn-mass companion: optimizing RV planet detections

Poster236Adam Stevenson; The Open University

Poster AreaMon 08:00 - 17:50

We present the RV analysis of a compact multi-planet system around a low-activity (log R’HK ~ 4.98) G5V star. A long-period outer planet with minimum mass of ~0.35 Mjup is detected despite hurdles caused by observation cadence, HARPS instrumental changes, and potential low-level stellar activity.Planetary signals have been explored using a nested sampling approach, with Np treated as a free parameter. We compare this with recursive period searches and Keplerian signal addition, which can provide incorrect solutions in studies of multiple low-amplitude signals (< 5 m s-1). Our current solution includes three significantly detected (BF >150) short period planets, on periods < 10d, with two near a 2:1 resonance. The minimum masses are all < 5 M⊕.The three close-in planets are likely products of inward migration, and the moderately-eccentric outer planet may be responsible: allowing us to study low-mass planet migration excited by a sub-Jovian perturbing object.

RV and transits
planets: detection, techniques: radial velocities

TI-DYE: an all-sky search for planets in nearby young associations

Poster493Madyson Barber; University of North Carolina at Chapel Hill

Poster AreaMon 08:00 - 17:50

Young planets offer insights into planet formation and evolution. However, the sample of young (<500 Myr) transiting planets is small (~40 planets) and heavily biased. Young planets from TESS were overwhelmingly identified using short-cadence data, excluding many of the more common low-mass stars. Using TESS full-frame imaging (FFI) and short-cadence (SPOC) light curves, we search tens of thousands of members of nearby young associations identified from Gaia. We incorporate a custom light-curve extraction pipeline optimized for separating stellar variability from instrumental signals. We search for planets using an updated version of the young-star optimized Notch and LoCOR transit-search pipelines. To account for survey completeness, we use planet injection-recovery tests and target membership probabilities. Among our early discoveries are: new extremely young (<50 Myr) candidates, multiple long-period single-transiting systems, and additional planets in previously identified young hosts. Preliminary tests suggest we can more than double the overall sample of young planets.

Formation and evolution
transits

TOI-201 and TOI-1670: New planets in warm Jupiter systems previously discovered by TESS

Poster110Ismael Mireles; University of New Mexico

Poster AreaMon 08:00 - 17:50

We report the discovery and validation of three new planets in two warm Jupiter systems first discovered by TESS. TOI-201 c is a super-Earth orbiting a young active star on a 5.85 d orbit interior to the warm Jupiter TOI-201 b. TOI-201 d is a Jupiter-size planet exterior to TOI-201 b that transited once during the 31 sectors in which the system was observed by TESS. TOI-1670 d is a sub-Neptune on a 123.06 d orbit exterior to the known sub-Neptune TOI-1670 b and warm Jupiter TOI-1670 c. We use TESS observations alongside follow-up observations to statistically validate the planets. The two systems add to the growing list of warm Jupiters with nearby companions. Furthermore, the two systems are well-suited for follow-up observations to further characterize their orbits and compositions, which would give insight into the formation and evolutionary history of these warm Jupiter systems.

RV and transits
Warm Jupiters

Towards the mysterious origins of warm Jupiters

Poster187Alexis Smith; German Aerospace Center (DLR)

Poster AreaMon 08:00 - 17:50

The origins of warm Jupiters (WJs) are unclear. If they formed beyond the snow line, then migration is required to bring them to their current orbits. It is unclear, however, which migration mechanism(s) are the most important. Obliquity (the angle between the stellar rotation and planetary orbital axes) is a key tracer of migration history. Dynamically violent, high-eccentricity migration leads to significantly misaligned orbits with large obliquities, whereas disc-driven migration should result in orbits coplanar with the stellar equator. In contrast to the hot Jupiters, the imprint of dynamical migration in WJs should not be erased through tidal interactions with the convective zone of their stars, because they are tidally detached. We have a VLT/ESPRESSO programme to measure the obliquities of an unbiased sample of eleven WJs, which will greatly increase the size of the measured sample. We present the motivation, target selection, and latest results from this observing programme.

Demographics & Architectures
obliquity, RossiterMcLaughlin

TRACE: Time-Reversible Algorithm for Astrophysical Close Encounters

Poster1650Tiger Lu; Yale University

Poster AreaMon 08:00 - 17:50

We present TRACE, a time-reversible hybrid integrator for the planetary N-body problem. Like hybrid symplectic integrators such as MERCURIUS, TRACE can resolve close encounters between pairs of planets. It can also accurately resolve close encounters with the central star, which current hybrid integrators cannot. In all our tested cases, TRACE offers comparable or better error performance to MERCURIUS with a computation time advantage of up to 9x for certain problems. We describe the derivation and implementation of TRACE and study its performance for a variety of realistic and relevant astrophysical systems. In ensemble tests of violent scattering systems, TRACE matches the high-order IAS15 on a statistical level. In large N} systems simulating lunar accretion, TRACE qualitatively gives the same results as IAS15 with a 47x speedup. TRACE is freely available within the REBOUND package.

Other
Gravitation

Tracking Tropical Cyclones in High-resolution GCM Simulations of TRAPPIST-1e with Varying Levels of Atmospheric CO2

Poster454Cole Smith; The University of Maryland

Poster AreaMon 08:00 - 17:50

While hurricanes are well-studied climate phenomena on Earth, further work is needed to determine whether cyclogenesis can occur on temperate rocky exoplanets and potentially impact their observable properties [1]. In this study, we conduct and analyze two separate ExoCAM GCM simulations of the prime temperate rocky target TRAPPIST-1e with varying background levels of 0.01 and 0.1 bars of carbon dioxide in the atmosphere along with 1 bar of nitrogen. We analyze the GCM output using TempestExtremes to track the formation and evolution of tropical cyclones and compare storm locations to expectations from Earth-based environmental favorability metrics. We detect tropical cyclones including hurricanes, tropical storms, and tropical depressions in our TRAPPIST-1e simulations, with storm strength and frequency dependent on the amount of background carbon dioxide. Investigations into their vertical structure bear similarities to tropical cyclones on Earth, and the locations of storms broadly agree with environmental favorability metrics.

Atmospheres
ExoCAM, Hurricanes, TRAPPIST1e, Tropical Cyclones

TRAPPIST-1 Atmospheric Reconnaissance with JWST: First Look at the Habitable-Zone Exoplanet TRAPPIST-1 f with NIRISS

Poster195Olivia Lim; Trottier Institute for Research on Exoplanets/University of Montreal

Poster AreaMon 08:00 - 17:50

Located in the solar neighborhood with seven Earth-sized, rocky, transiting planets, three which being in the habitable zone, TRAPPIST-1 may be our best shot at detecting and potentially characterizing atmospheres on small temperate exoplanets. So far, the search for atmospheres on TRAPPIST-1 planets has been an exciting adventure full of challenges. Transit observations with HST rejected cloud-free, hydrogen-rich atmospheres on all seven planets. Secondary eclipse observations of TRAPPIST-1 b and c with JWST also rejected any thick atmospheres, especially ones rich in CO2 for planet c. In transmission, JWST revealed strong evidence for stellar contamination from unocculted spots and faculae. Is there still hope to find atmospheres on the outer, cooler planets? In this talk, we will present the first JWST transmission spectra of the habitable-zone planet TRAPPIST-1 f obtained with NIRISS, and discuss lessons learned from previous JWST observations of this unique system and possible strategies for the future.

JWST Results
Habitable zone, JWST, Transmission spectroscopy, TRAPPIST1

Two temperate Earth-mass planets orbiting the nearby star GJ

Poster432Alejandro Suárez Mascareño; Instituto de Astrofísica de Canarias

Poster AreaMon 08:00 - 17:50

Nearby low-mass stars are ideal candidates to search for Earth-like exoplanets. The large angular separation of their orbits, even at short periods, makes non-transiting planets amenable for atmospheric characterization with future facilities. We studied the M-dwarf GJ 1002 (< 5 pc away) using RVs and activity indicators from ESPRESSO and CARMENES. By performing a state-of-the-art multi-dimensional GP model, we detrended the data from stellar activity and detected two Earh-mass planets orbiting within the habitable zone of the star. GJ 1002 b is a 1.08 Me planet with an orbital period of 10.3 days, and GJ 1002 c is a 1.36 Me planet with an orbital period of 21.2 days. The angular orbital distance of GJ 1002 c makes it a good candidate for atmospheric characterisation via High Dispersion Coronography (HDC) spectroscopy with the future ANDES spectrograph for the ELT, or Nulling interferometry with the future space mission LIFE.

RV and transits
CARMENES, Earthlike planets, ESPRESSO, Mdwarfs

Two transiting super-Earths orbiting the nearby K-dwarf TYC 6398-132-1

Poster436Alejandro Suárez Mascareño; Instituto de Astrofísica de Canarias

Poster AreaMon 08:00 - 17:50

Transiting exoplanets offer a unique opportunity to characterise the internal composition of exoplanets, which in turn provides unique insights on their architecture, formation, and evolution.TYC 6398-132-1 has a short-orbit planet candidate announced by TESS (TOI 238.01). We performed a combined photometric and radial velocity analysis of the system, using TESS, ESPRESSO and HARPS data, taking advantage of state-of-the-art multi-dimensional Gaussian processes. We detected the signal induced by TOI 238.01 in the radial velocity time-series and additionally detect and characterize another transiting planet.TYC 6398-00132-1 b is a hot super-Earth, with a radius of 1.4 Re, a mass of 3.4 Me and an orbital period of 1.27 days. TYC 6398-00132-1 c is most likely a water world, with a radius of 2.2 Re, a mass of 6.7 Me, and an orbital period of 8.47 days.

RV and transits
ESPRESSO, TESS, water worlds

Understanding the origins of the radius valley

Poster38Jesper Nielsen; University of Copenhagen

Poster AreaMon 08:00 - 17:50

The origins of the radius valley is still unknown. Previous work have explained it through two different mass-loss processes: photoevaporation (Owen & Wu 2017) and core-powered mass-loss (Ginzburg et al. 2018), with observations seemingly supporting core-powered mass-loss (Berger et al. 2023). Recent studies however, indicate that the valley can form without the need for mass-loss (Lee et al. 2022). Previous studies have so far used observational data to construct a planet sample which can be affected by observational biases. We therefore aim to investigate the origins of the radius valley from the onset of planet formation by simulating core formation by pebble accretion and the subsequent gas accretion onto the cores. After the dispersal of the protoplanetary disc, we let the planet cool down and thus contract. We can then compare the simulated radius distribution with observations and hopefully shed light onto the origins of the radius valley.

Formation and evolution
Atmospheres, Demographics, Formation, Radii

Unlocking the Complexity of 3D Exoplanet Atmospheres: A Combined Modelling Approach and Observational Implications

Poster128Sven Kiefer; Institute of Astronomy, KU Leuven

Poster AreaMon 08:00 - 17:50

We present the results from our combined modeling approach of a 3D cloudy atmosphere model, applied to the case of HATS-6b orbiting an M-dwarf star. Our methodology involves a series of iterative interactions between the full 3D General Circulation Model expert/MITgcm and a detailed kinetic cloud formation model. Through this integrated effort we achieve a predictive understanding of HATS-6b's atmospheric properties, aligning with the observational capabilities of JWST, including NIRspec Prism and MIRI LRS instruments. The presence of clouds induces a temperature inversion on the planet's illuminated hemisphere, resulting in cooler temperatures at greater atmospheric depths. Observations at wavelengths above 1 micron offer promising prospects for the detection of molecular features, such as H2O and CH4, as well as potential signatures from cloud materials. Our approach offers a multifaceted perspective on the complex interplay of atmospheric dynamics and chemical process, and on observational potential in the study of exoplanets.

Atmospheres
Clouds, General Circulation Model (GCM), HATS6b

Unraveling the Origin of Detected Species on WASP-178b with ESPRESSO

Poster340Julia Seidel; European Southern Observatory; Yuri Damasceno; Instituto de Astrofísica e Ciências do Espaço

Poster AreaMon 08:00 - 17:50

WASP-178b, distinguished as one of the most bloated ultra-hot Jupiters known, hasgarnered significant attention and prompted dedicated observations with the HST and theCHEOPS. As part of the ESPRESSO GTO, we obtained two transits resulting in the detectionof atmospheric sodium and H-alpha, along with a tentative detection of magnesium. Givenits importance as an observed JWST target, understanding the origin of these detections isparamount. Are these signals truly of planetary origin? In this presentation, we elucidatethis question by examining the relative light curves for each species, providing evidence toaddress the possibility of an extra-atmospheric source.

Atmospheres
Atmospheric Detection, ESPRESSO, JWST Target

Unveiling Sub-Neptune Atmospheres: A simulated search for biosignatures at high resolution with the ELT

Poster6Alejandro Sánchez López; Instituto de Astrofisica de Andalucia (IAA-CSIC)

Poster AreaMon 08:00 - 17:50

We will present realistic simulations of high-resolution observations of sub-Neptune atmospheres using cutting-edge instruments, including CRIRES+ and the upcoming ELT instruments METIS and ANDES. We assess the detectability of atmospheric compounds (e.g., CO2, H2O, CH4, O2, or DMS) across various wavelength ranges for some of the most optimal sub-Neptune targets in transmission and emission. By exploring different observation strategies, we aim to identify optimal approaches for detecting habitable conditions and probing the potential interplay between exo-atmospheres and biospheres with the next generation of ground-based instrumentation.

Habitability
Atmospheres, Biomarkers, ELTs, SubNeptunes

Using high resolution cross correlation spectroscopy to probe oxygen fugacity regimes in lava ocean worlds

Poster502Spandan Dash; University of Warwick

Poster AreaMon 08:00 - 17:50

Short period ultra-hot rocky planets, which have lost most of their primary atmosphere due to their host star radiation, are expected to only have a secondary atmosphere formed from vaporisation of the mantle. The mantle composition itself is dependent on the oxidation state (quantified by fugacity). Here we investigate whether high-resolution cross-correlation spectroscopy can be used to place constraints on the fugacity regimes in such exoplanets. To accomplish this, we use atmospheric P-T and abundance profiles generated by a suite of models taking oxygen fugacity of the mantle as a free parameter, and simulate nights of dayside observations between 0.5-2.6 µm assuming instrumental parameters of currently used spectrographs. We then quantify the conditions that would enable us to differentiate between these fugacity regimes. Finally, we evaluate whether it is already possible to do so using current facilities, or would require observations from the upcoming E-ELT.

Atmospheres
atmosphereinterior connection, high resolution cross correlation spectroscopy, lava ocean worlds

Using high-contrast binaries to improve the characterisation of exoplanet atmospheres

Poster517Daniel Sebastian; University Of Birmingham

Poster AreaMon 08:00 - 17:50

High-resolution cross-correlation techniques are a powerful tool to explore exoplanet atmospheres. Especially its application to high signal-to-noise data allows to test models of exoplanet atmospheres, including winds, and the spatial distribution of molecules.

We introduce the application of high-resolution cross-correlation techniques to binary stars known to host circumbiary planets. In particular we focus on eclipsing, high-contrast binaries consisting of a solar-type star and a low mass M-dwarf companion. These binary systems feature brightness ratios similar to those of well-analysed ultra-hot jupiters. Since the spectral features of low-mass stars are well known, we can both detect the atmospheric signal of the low-mass companion and develop tools to accurately measure the mass of both stars.

We show that this application can be extended to establish phase-resolved tracing of molecules within exoplanet atmospheres of ultra-hot jupiters using upcoming large aperture instrumentation like the ELT.

Atmospheres
spectroscopic

Using Machine Learning to predict planetary detection

Poster173Jeanne Davoult; Universität Bern

Poster AreaMon 08:00 - 17:50

After thousands of exoplanet detections over the last 30 years, detection methods are becoming increasingly efficient, with the aim of detecting smaller and cooler planets. Such detections require a considerable amount of observation time, and in order to avoid blind searches, we propose here an exoplanet prediction method. Recent years have seen the discovery of multi-planet systems with distinctive patterns, like 'Peas-in-a-Pod'. These 'architectures' lead us to believe that the planets are interconnected and that their formation carries the trace of the formation of their neighbors. Based on this hypothesis, the known planets of a system are then clues to the profile of the unknown planets of a system.Trained on populations of synthetic planetary systems derived from the Bern model, we present here an algorithm capable of predicting the approximate size and position of missing planets based on the characteristics of the system and its known planets.

Demographics & Architectures
Architecture, Detection, Machine Learning, Planetary systems

Vapor equilibrium models of rocky planets growing by pebble accretion

Poster431Marie-Luise Steinmeyer; Globe Institute, University of Copenhagen

Poster AreaMon 08:00 - 17:50

Planets growing by pebble accretion acquire a hydrostatic envelope during their growth process. The temperature in the envelope becomes hot enough to sublimate the incoming silicate pebble before they reach the surface of the planet. I will present a vapor equilibrium model of envelopes enriched in SiO of low mass rocky planets. The model includes the stabilizing effect of condensation on the envelope. The resulting build up of an inner radiative region increases the temperature and pressure in the inner envelope compared to pure H/He envelopes. For Mpl>0.8 M⊕ the temperature and pressure exceed the critical point of SiO and the planet is covered in a supercritical magma ocean. Furthermore, we show that in contrast to previous work, direct core growth happens throughout the whole growth period of low mass rocky planets.

Formation and evolution
pebble accretionrocky planets

VHS 1256 b, HIP 99770 b, AF Lep b: Expected Thermal and Reflected Light Polarization

Poster51Maxwell Galloway; University of Central Florida

Poster AreaMon 08:00 - 17:50

Direct imaging of planetary mass companions and brown dwarfs has revealed similar spectra to L/T transition brown dwarfs, including hints of rotational variability. Polarization, being sensitive to macro- and micro-physical properties of clouds, can break degeneracy in potential cloud structures from flux-only observations. We used a climate model code (PICASO) and a 3D radiative transfer code (ARTES) to model potential light curves and select spectra for VHS 1256 b, HIP 99770 b, and AF Leporis b in the NIR. We explored a range of potential cloud formations, sizes, and cloud sedimentation parameter values. In this presentation, we will discuss the effect of temperature, gravity, cloud parameters, and inclination on the observed signals and potentially observable trends. The models presented here are part of a larger grid that will be given open-access to the community and can be used to aid in the characterization of directly imaged exoplanets and brown dwarfs.

Direct Imaging and Interferometry
Brown dwarfs, planetary mass companions, polarization

WASP-18b - a test case for deep dynamics and radius inflation

Poster364Ludmila Carone; Space Research Institute (IWF), Graz

Poster AreaMon 08:00 - 17:50

WASP-18b is one of the most massive ultra-hot Jupiters that has been observed to date. What makes this planet stand out compared to its highly inflated siblings? We present first results that show that zonal wind jets can extend unusually deep into the interior for this planet reaching at least 1000 bar. We further explore how the depth of wind jets affects the temperature structure as well as energy & momentum transport below the photosphere compared to the highly inflated ultra-hot Jupiter WASP-76b for 1x and 10x solar metallicity. We finally stress that the understanding of the atmosphere layers between 1 and 1000 bar is a necessary prerequisite for understanding radius inflation.

Atmospheres
3D GCM, Inflation, Interior

WASP-4 b’s apparent orbital decay can be explained by the Rømer effect

Poster446Jan-Vincent Harre; German Aerospace Center (DLR), Institute of Planetary Research

Poster AreaMon 08:00 - 17:50

WASP-4 b is a hot Jupiter and one of the prime candidates for orbital decay, with measured decay rates of about -7 ms/yr. The recent radial velocity discovery of a massive planetary candidate “c” on a long period (~7000 d) orbit, poses the question if the apparent TTVs could be caused solely by this planet. Due to the high mass of planet c (~5 MJup), the system’s center of mass is shifted by about 9 times the radius of the host star, meaning that the star’s relative position changes over the orbital period of planet c. This introduces an additional light-time effect that needs to be considered when analysing the transit timings of the hot Jupiter. The magnitude of the time-shift is about ~40s, which could, due to the uncertainties in the time of inferior conjunction of planet c, enhance the apparent orbital decay signature, but also completely negate it.

RV and transits
Orbital decay, Photometry, Transit timing variations

When, where, and how many planets end up in first-order mean motion resonances?

Poster351Shuo Huang; Leiden Observatory

Poster AreaMon 08:00 - 17:50

The theory of Type I migration has been widely used in many studies. Transiting multiplanet systems offers us the opportunity to examine the consistency between observation and theory, especially for those systems harboring planets in resonance. The displacement of these resonant pairs from exact commensurability hints at their migration and eccentricity-damping histories. Here, we adopt a probabilistic approach, characterized by two distributions -- appropriate for either the resonant or non-resonant planets -- to fit the observed displacement. We find that about 15 percent of exoplanets are in first-order resonance and the ratio of eccentricity-to-semimajor axis damping is consistent with Type-I migration theory. In addition, our modeling finds that most of the resonant pairs park themselves at the migration barrier, indicating early planet formation (gas-rich). Furthermore, we obtain an upper limit of the disc surface density at the time the planets are locked in resonance by assessing the resonance strength.

Demographics & Architectures
celestial mechanics, planet–disc interactions, planets and satellites: dynamical evolution and s, planets and satellites: formation

Witnessing planet formation as it happens; HR diagram tracks of forming planets

Poster151Benedikt Gottstein; Universität Bern

Poster AreaMon 08:00 - 17:50

My work utilizes the Bern model, a 1D planet formation code, to derive luminosity and effective temperature profiles for planets throughout their formation and evolution. Our primary objective is to construct tracks on the Hertzsprung-Russell diagram (HR Diagram) by exploring a wide parameter space, including planet mass, orbital distance, disk properties, and formation processes. To enhance the accuracy of our predictions, we incorporate validated results from 3D simulations for both intrinsic and shock luminosity calculations. These HR tracks provide a novel and fundamental framework for the interpretation of observations of forming planets, contributing significantly to our understanding of the various stages of planetary growth. By addressing the question "Can we identify evolutionary stages of planetary growth?", our research aims to advance the field of planet formation and facilitate realistic predictions for future observations, shedding light on the intricate processes that govern planetary birth and development.

Formation and evolution
Luminosity, Planet formation, Planetary HRDiagram

10:00 - 10:30 Plenary Talks 1

1. The Highlights from an 82-hour JWST NIRSPEC+NIRISS Survey of Five Water-World Candidates

Plenary Talk1522Björn Benneke; University of Montreal

Grote ZaalMon 10:00 - 10:30

One of the most fundamental results in the study of exoplanets has been the finding that small planets are extremely abundant in the Universe and that they are bifurcated into seemingly two separate population: rocky super-Earths and gas-rich sub-Neptunes. Strikingly, recent studies have suggested the existence of a long-hypothesized new category of planets, referred to as water worlds, representing larger and warmer planetary versions of the volatile-rich icy moons in the Outer Solar System. In this talk, we will present the highlights from our 82-hour JWST/NIRSPEC+NIRISS survey probing the transmission spectra of five water-world candidates in unprecedented detail. We discuss the main findings regarding the prevalence and diversity of volatile-rich water worlds, based on molecular detections on at least three planets in our survey. We put particular emphasis on the temperate planet TOI-270d for which we detect, for the first time, a high-metallicity atmosphere rich in carbon, oxygen, and sulfur.

Atmospheres
Atmospheric chemistry and dynamics, Implication for planet formation and evolution, JWST Large GO Survey

2. Demographic Results from the TESS Grand Unified Hot Jupiter Survey

Plenary Talk416Samuel Yee; Center for Astrophysics | Harvard & Smithsonian

Grote ZaalMon 10:00 - 10:30

The demographics of exoplanets are a key lever we have to understand how they form and evolve. However, because hot Jupiters are intrinsically rare, our knowledge of their statistics has been limited by small number found by any individual survey, and the heterogeneity of the overall sample. Over the past two years, we have been conducting an extensive observational campaign to assemble a magnitude-limited sample of transiting hot Jupiters unified by the all-sky transit search of TESS. We observed >200 candidates and confirmed >80 new planets, and combined this with previously known objects to create a homogeneous sample of 400 hot Jupiters. I will present the first demographic results to emerge from this survey, including the >4-sigma detection of the "three-day" pile-up in the period distribution, the dependence of their occurrence rate on host star metallicity and mass, and comparisons with smaller and longer-period planets.

Demographics & Architectures
Demographics, Hot Jupiters, Transit Survey

11:30 - 12:00 Plenary Talks 2

1. High-resolution spectroscopy of directly imaged planets and brown dwarfs with KPIC: abundances, spins, and RVs

Plenary Talk261Jerry Xuan; California Institute of Technology

Grote ZaalMon 11:30 - 12:00

The Keck Planet Imager and Characterizer (KPIC) is a fiber-fed spectrograph for exoplanet characterization. We have collected K-band high-resolution spectra (1.9-2.5 micron, R~35,000) for about 30 directly imaged exoplanets and brown dwarf companions. I will overview science results from KPIC. First, I present new high resolution KPIC spectra on the most challenging imaged exoplanets (HR 8799 bcde, AF Lep b) and a population-level analysis of the compositions of ~10 planetary-mass companions (m~10-30 MJup). We find nearly solar C/O and metallicities for these "planetary-mass companions," suggesting that they are more consistent with forming via direct gravitational collapse than core accretion. I also summarize six new 12CO/13CO measurements, another potential formation tracer. Besides atmospheric compositions, KPIC is enabling precise radial velocity and spin measurements of directly imaged companions. I present the first results of our search for exomoons around substellar companions and dozens of new spin measurements.

Atmospheres
Atmospheric composition

2. When Worlds (probably) Collide: An exoplanet collision remnant around ASASSN-21qj

Plenary Talk685Richelle van Capelleveen; Leiden Observatory

Grote ZaalMon 11:30 - 12:00

The star ASASSN-21qj underwent an infrared brightening followed by an optical eclipse which we explain as the result of the collision of two ice giant exoplanets, followed by the transit of the resultant debris cloud. The remnant is called a synestia, whose silicate and water vapour dominated photosphere is several times larger than the parent star, initially radiating with 3% of the star's luminosity at a temperature of 1000 K, but subsequently halving in flux every two months. We will discuss the observational consequences of this synestia and present the latest observations along with the implications of such giant impact events.

Formation and evolution
giant impact, ice gas giant, JWST

13:30 - 14:30 Parallel Talks 1

1. The HUMDRUM Survey of Nearby Transiting M Dwarf Planets with MAROON-X: An Update

Parallel Talk338Madison Brady; University of Chicago

AalmarktzaalMon 13:30 - 14:30

M dwarfs give us a unique opportunity to precisely study the formation, composition, and habitability of rocky planets. With its optical/NIR wavelength coverage and high precision, the MAROON-X spectrograph is ideal for studying M dwarf planets. In this talk, I provide an update on HUMDRUM (HUnting for M Dwarf Rocky planets Using MAROON-X), a volume-limited radial velocity survey of TESS planet candidates around nearby M dwarfs with MAROON-X. The data allow us to study planet compositions and identify targets for JWST follow-up. Our improved mass precisions (frequently around 10%) show that most transiting M dwarf planets are rocky, with only a few planets consistent with volatile-rich compositions. We also find a bimodal distribution of planet masses, with an underdensity of planets from 4-6 Earth masses. Finally, the mass function increases towards small planets, indicating that Earth-composition planets of 1-3 Earth masses are a common outcome of planet formation.

RV and transits
Radial Velocities, Rocky Planets

2. Results and new detections from the BEBOP search for circumbinary planets

Parallel Talk334Thomas Baycroft; University of Birmingham

AalmarktzaalMon 13:30 - 14:30

The BEBOP (Binaries Escorted By Orbiting Planets) survey is a search for circumbinary planets using the radial velocity spectrographs HARPS and SOPHIE.

Circumbinary systems are an important testing ground for planet formation theories as the dynamically complex influence of the binary makes planet formation and survival more difficult. Obtaining a larger sample of such planets, accurately characterised, is therefore vital to further our understanding. Progress has been made to overcome/circumvent the observational difficulties that have been hampering circumbinary planet detection. From radial velocities, the BEBOP survey has achieved sensitivity down to Saturn mass planets across a wide range of orbital periods for many targets.

I will present the latest results from the survey including confirmed planets such as BEBOP-3b the circumbinary planet with the highest eccentricity. I will compare the planets and candidates from BEBOP to the transiting circumbinary planet population and the population of planets around single stars.

RV and transits
Circumbinary planets, Eccentricity, Eclipsing binaries, Occurrence rates

3. AESTRA: Deep Learning for Precise Radial Velocity Estimation in the Presence of Stellar Activity

Parallel Talk1454Yan Liang; Princeton University

AalmarktzaalMon 13:30 - 14:30

Stellar activity interferes with precise radial velocity measurements and limits our ability to detect and characterize exoplanets, particularly Earth-like ones. We introduce AESTRA, a deep learning method for precise radial velocity measurements. It combines a spectrum auto-encoder, which learns to create realistic models of the star's rest-frame spectrum, and a radial-velocity estimator, which learns to identify true Doppler shifts in the presence of spurious shifts due to line-profile variations. Being self-supervised, AESTRA does not need "ground truth" radial velocities for training, making it applicable to exoplanet host stars for which the truth is unknown. In tests involving 1,000 simulated spectra, AESTRA can detect planetary signals as low as 0.1 m/s even in the presence of 3 m/s of activity-induced noise and 0.3 m/s of photon noise per spectrum. The results of applying AESTRA to real-world data, including solar data from the NEID spectrograph, will be presented.

RV and transits
Deep Learning, Extremely Precise Radial Velocity, Stellar Activity Mitigation

4. NOMADS: A statistical survey of planet mass and density within the Neptunian Desert

Parallel Talk56David Armstrong; University of Warwick

AalmarktzaalMon 13:30 - 14:30

I will present results from the NOMADS survey, a large programme on HARPS targeting TESS planets in the Neptunian desert. The survey utilised a merit function to select targets, leading to a defined sample of ~40 TESS candidates with precise radial velocity follow-up. Recent discoveries have shown that the Neptunian desert is not barren, and in fact contains extremely dense planets such as TOI-849b and TOI-1853b with an unusual formation history. Key discoveries from our survey include TOI-332b, TOI-3071b and TOI-3261b, a set of planets deep in the desert demonstrating that dense, desert Neptunes represent a population of planets rather than a few individual cases. Using the observed sample I will present preliminary statistics on the desert planet population, including in planet density, allowing a deeper understanding of how these planets formed and reached their present state.

RV and transits
Neptunian Desert, Populations, Radial Velocity Surveys

1. Planets in the Neptune Desert Are "Hot Jupiters Gone Wrong"

Parallel Talk1122Shreyas Vissapragada; Harvard University

BreezaalMon 13:30 - 14:30

We present multiple lines of evidence suggesting that the extreme planets residing within the Neptune desert are in fact the exposed high-metallicity cores of gas giants. First, we show that desert-dwellers preferentially orbit metal-rich stars, similar to the hot Jupiters -- hinting at common formation/evolution pathways. We then present the inaugural discovery from the new HARPS-N Hot Neptune Initiative: the first planet deep within the Neptune desert with a detected stellar companion. The companion probably drove high-eccentricity migration of a Jupiter-like progenitor that partially disrupted, as the planet resides at twice the tidal disruption radius for a Jupiter-sized planet. Finally, using new helium 10830 observations, we demonstrate that the outflows of Neptune desert-dwellers are far weaker than expected, likely due to their high envelope metallicities. Altogether, these planets appear consistent with would-be hot Jupiters that underwent catastrophic envelope loss, exposing metal-rich gas at depth: they are "hot Jupiters gone wrong."

Formation and evolution
Atmospheric Escape, Hot Neptunes, Radial Velocities

2. The MOPYS survey: Measuring Out-flows in Planets orbiting Young Stars via He detection

Parallel Talk315Jaume Orell-Miquel; Instituto de Astrofísica de Canarias (IAC)

BreezaalMon 13:30 - 14:30

During the early stages of planetary formation, planets suffer severe changes in their physical properties due to internal and external forces, which also affect their primordial atmospheres. The study of planets at early stages and its comparison with the already mature planet population is crucial for a better comprehension of different processes, such as: planet formation, evaporation of primary atmospheres of rocky planets, gas accretion or inflation.

As part of a large project to investigate the evolution, out-flow, and evaporation of exoatmospheres, we present the first results of the MOPYS survey. We observed +20 young exoplanets, mainly sub-Neptunes, targeting the two principal ground-accessible evaporation tracers: Halpha, and He triplet. We complemented our survey with available literature results. This broad range of studied planets allow us to obtain a general view of evaporation processes across planetary parameters, and find novel relationships to explain the evaporation processes.

Atmospheres
He I detection

3. HeI survey of planets on the Neptunian desert's edge considering stellar activity with GIARPS

Talk748Gloria Guilluy; INAF-OATO

BreezaalMon 13:30 - 14:30

One of the most prominent features in the exoplanet population is the dearth of Neptunes on very short orbits (Period<10 days). Given the proximity of those planets to their stars, photoevaporation can be the key driver in clearing the desert. Direct observations of extended atmospheres are essential to link atmospheric escape to the desert formation.The metastable near-infrared helium triplet (HeI) has been identified as a potent proxy for atmospheric escape. Currently, we are shifting from single-planet HeI detections to conducting HeI surveys of more planets. I will present the outcomes of a homogeneous HeI survey conducted along the edges of the Neptunian desert with the GIANO-B@TNG spectrograph. A key aspect of our analysis is the simultaneous monitoring of stellar activity diagnostic within HARPS-N spectra (e.g., Hα). Neglecting stellar activity may lead to inaccurate mass-loss estimations and misleading insights into the desert structure and origin.

Atmospheres
stellar activity

4. A study of atmospheric escape of exoplanets using CARMENES He I 10830 A measurements

Parallel Talk1033Manuel López-Puertas; IAA, CSIC

BreezaalMon 13:30 - 14:30

Understanding the role of hydrodynamic escape in planetary mass loss and evolution is widely acknowledged. While this mechanism may not substantially alter the state of hot Jupiters, it significantly influences the evolution of lower-mass planets. However, comprehending the entire process, from stellar irradiation to planetary response, remains challenging due to limited observations.

Recent high-resolution absorption measurements of the He I triplet state at 10830 Å, have opened a crucial avenue for studying exoplanetary upper atmospheres. Notably, the CARMENES high-resolution spectrograph at the CAHA Observatory has provided a wealth of such measurements for several diverse exoplanets.

Here, we will showcase these observations alongside a comprehensive analysis, to elucidate key parameters of these planets' upper atmospheres, including mass-loss rates, H/He abundances, line equivalent widths, and the various hydrodynamic escape regimes they exhibit. We find that the breadth of observed planets allows us to draw initial overarching conclusions.

Atmospheres
Hydrodynamic escape, Photoevaporation

1. Identifying and locating cloud species from their mid-IR vibrational mode absorption

Parallel Talk314David Grant; University of Bristol

Grote ZaalMon 13:30 - 14:30

Clouds are prevalent in many of the exoplanet atmospheres that have been observed to date. However, the exact composition of these clouds is largely unknown. In this talk, I will present JWST mid-Infrared spectroscopy of the transiting exoplanets HD 209458b and WASP-17b. We detect cloud-particle vibrational-mode absorption in both cases and identify the cloud species. These planets have equilibrium temperatures ranging from 1400 to 1700 K, and we show how the clouds forming changes across these temperatures. These results have important implications for the measured global composition of an exoplanet’s atmosphere, and I will show how (1) the clouds may sequester various molecules away from the gas-phase, and (2) the spatial distribution of clouds may also be measured with transmission mapping techniques. Both of these effects, sequestering and the spatial distribution, must be incorporated when making accurate measurements of an exoplanet’s overall carbon-to-oxygen ratio and metallicity.

Atmospheres
Clouds, JWST

2. JWST measurements of $^{13}$C, $^{18}$O and $^{17}$O in the atmosphere of super-Jupiter VHS~1256~b

Parallel Talk129Siddharth Gandhi; University of Warwick; Sam De Regt; Leiden University

Grote ZaalMon 13:30 - 14:30

Isotope ratios have recently been measured in the atmospheres of directly-imaged and transiting exoplanets from the ground, and the arrival of JWST opens new avenues in atmospheric characterisation. In this talk I will discuss our recent work in constraining the carbon and oxygen isotopes $^{13}$C, $^{18}$O and $^{17}$O from CO in the atmosphere of the directly-imaged companion VHS~1256~b with NIRSpec. We find $mathrm{^{12}C/^{13}C=62^{+2}_{-2}}$, in between previous measurements for companions ($sim$30) and isolated brown dwarfs ($sim$100). The oxygen isotope ratios are $mathrm{^{16}O/^{18}O =425^{+33}_{-28}}$ and $mathrm{^{16}O/^{17}O=1010^{+120}_{-100}}$. All of the ratios are lower than the local inter-stellar medium and Solar System, suggesting that abundances of the more minor isotopes are enhanced, potentially driven by isotope fractionation in protoplanetary disks. This highlights the power of JWST to constrain isotopes in exoplanet atmospheres, and shows great promise in determining formation histories in the future.

Atmospheres
Isotope ratios, JWST, Retrievals

3. Characterizing the atmospheres of giant exoplanets around M dwarfs with JWST

Parallel Talk95Caleb Cañas; NASA Goddard Space Flight Center

Grote ZaalMon 13:30 - 14:30

Short period, giant exoplanets around M dwarf stars (GEMS) represent a growing exoplanet population that is difficult to reconcile with existing theories of planetary formation. I will discuss the efforts to characterize the atmospheres of these planets as a means of investigating formation pathways with a large JWST Cycle 2 survey. This program will observe 7 GEMS to determine atmospheric and bulk metallicities. I will present the results for TOI-5205 b, a Jupiter analogue orbiting a mid-M dwarf and the first of these GEMS observed with transmission spectroscopy, and motivate the power of this survey to investigate how these planets form.

JWST Results
Atmospheres, Gas giants, M dwarfs

4. Partial Phase Curve of the Highly Eccentric Hot Jupiter HD80606b Observed With NIRSpec

Parallel Talk1527James Sikora; Lowell Observatory

Grote ZaalMon 13:30 - 14:30

High-eccentricity gas giant planets serve as unique laboratories for studying the thermal and chemical properties of H/He-dominated atmospheres. In certain cases, the orbit-induced changes in incident flux can significantly alter the atmosphere’s temperature profile and allow the thermal timescales, chemical timescales, and the composition of aerosols to be measured. One particularly remarkable case is that of HD80606b (M=4.2 Mjup, R=1.0 Rjup, P=111 d, e=0.93), which experiences an increase in incident flux of nearly three orders of magnitude between the apoastron, when the planet is 0.9 au from its host star, and the periastron, at 0.03 au. Here we will present results from JWST NIRSpec partial phase curve observations of HD80606b’s periapse passage. These observations span a 21 hr window encompassing both the eclipse and the periastron and reveal an atmosphere that is undergoing rapid changes in terms of its chemical composition and thermal structure.

JWST Results
eclipse

14:40 - 15:40 Parallel Talks 2

1. The CARMENES search for exoplanets around M dwarfs

Parallel Talk409Stefan Dreizler; Institut für Astrophysik und Geophysik

AalmarktzaalMon 14:40 - 15:40

The results from the CARMENES surveys have significantly extended our knowledge about exoplanets around M-dwarfs. The Data Release from the Guaranteed Time Observations (Ribas+, 2023) contains nearly 20000 spectra delivering high-precision radial velocity measurements for 362 M-dwarfs, which make up 70% of the known M-dwarfs within 10 pc accessible to CARMENES. Within the Legacy Plus survey, the number of observations for all target stars is currently increased to 50 epochs. We expect more than 70 planet discoveries in total, nearly half of them from TESS follow-up, allowing to place exoplanet systems around low-mass stars into the context of planet formation, evolution, planet system architectures, and the study of their demographics and atmospheres. The exoplanet discoveries are supplemented by insights into stellar properties of M-dwarfs, such as fundamental stellar parameters, stellar activity, and star-planet interaction. The talk summarizes these diverse aspects of the CARMENES survey and highlights specifically interesting planetary systems.

RV and transits
Complementary stellar science, M dwarfs, Radial Velocity Survey, Transit followup

2. Impact of stellar variability on future Earth-like planets detectability and characterization in radial velocity

Parallel Talk294Nadège Meunier; Université Grenoble Alpes

AalmarktzaalMon 14:40 - 15:40

It is now well accepted that stellar activity prevents detection of low mass planets around solar type stars when using the radial velocity technique. In addition to the impact of dark spots and bright plages, surface flows at different time scales (granulation, supergranulation, meridional circulation) also lead to RV variations (Meunier 2021), most with a much larger amplitude than an Earth-like signal. After introducing this challenge and the stellar processes affecting RVs, we will present our approach: we used our knowledge of solar activity to produce a large amount of realistic synthetic time series for other solar-type stars. We will show recent results (Meunier+2023) base on large-scale blind tests performed to better understand some limitations in mitigating techniques, to estimate the performance (detection and mass characterization), focusing on Earth-like planets in the habitable zone around solar-type stars. We will discuss possibilities to improve performance in order to reach PLATO objectives.

RV and transits
exoplanet, rv technique, stellar activity

3. Radial Velocities in the near-infrared and magnetic fields: beauties and challenges with CFHT/SPIRou

Parallel Talk451Claire Moutou; IRAP

AalmarktzaalMon 14:40 - 15:40

Characterizing exoplanet systems requires both detecting multiple planetary signals with various methods and getting the widest possible knownledge of the planetary environment, driven by stellar properties. Among those, the stellar magnetic field is particularly important for its role in shaping planetary environments along the system's lifetime. With the NIR spectropolarimeter SPIRou in operations since 2019 at the Canada-France-Hawaii Telescope, it is possible to simultaneously measure the precise RV time series and monitor the stellar host circular polarization. A 5yr monitoring survey of about 100 stars is being carried with SPIRou, to be complete mid-2024. Stellar fields of 1-500 Gauss and new telluric planetary candidates got revealed. In this talk, I will review how precise NIR radial velocities are obtained with SPIRou and allows characterizing planetary systems of low-mass stars and very young stars, while it permits deriving the magnetic field properties of the stellar hosts.

RV and transits
magnetic field

4. HD 20794: A bright G6V star observed with ESPRESSO and HARPS

Parallel Talk490Nicola Nari; Light Bridges S.L.

AalmarktzaalMon 14:40 - 15:40

HD 20794 is a G6 star known for hosting a multi-planetary system. This star is a bright target and has shown extraordinary stability over tens of years of HARPS observations, making it a preferential candidate for extreme-precision RV surveys. With ESPRESSO, we reach an RMS of 76 cm/s.

We join data taken during the ESPRESSO GTO with the YARARA-corrected HARPS historical time series for a combined analysis, taking advantage of the dense sampling of HARPS. We present the full analysis of the system, which considers radial velocities and all available activity indicators. Our goal is twofold – One we aim to test the performance of ESPRESSO in the observation of solar-type stars. Two we want to validate the planetary nature of all published planetary signals, including of the recently announced candidate super-Earth, orbiting close to the habitable zone of the star, with a period of more than 600 days.

RV and transits
EPRV, ESPRESSO, YARARA

1. Unveiling Repeated and Modulated Star-Planet Interaction Signals in a Benchmark Neptune-sized Planet.

Parallel Talk310Daniel Revilla Martínez de Albéniz; Instituto de Astrofísica de Andalucía

BreezaalMon 14:40 - 15:40

Attributing a signal to Magnetic Star-Planet Interaction (SPI) is challenging because of its fluctuating and multifactorial nature. To date, no detection has been repeated and thus confirmed. We have analyzed, in search of SPI signals in a benchmarck star hosting a close-in Neputne-size planet, the high-cadence spectroscopic observations of multiple instruments spanning over one magnetic cycle of the star. Our analysis focuses on time series of chromospheric activity indicators, revealing multiple signals consistent with SPI. In particular, we identify two chromospheric temporal enhancements, one in 2008 and the second ~8 years later after a complete magnetic cycle, modulated at the synodic frequency of the system in both CaII H&K observations from HARPS and in CaII IRT a data from CARMENES. This constitutes the first repeated and potentially confirmed detection of SPI, providing us with insight into the exoplanet magnetic field and its possible habitability.

Star-planet interactions
activity, chormosphere, magneticcycle, SPI

2. Exo-space weather: Linking multi-wavelength, contemporaneous observations and models of star-planet interactions

Parallel Talk1202Aline Vidotto; Leiden University

BreezaalMon 14:40 - 15:40

Transmission spectroscopic is a powerful technique to probe the atmospheres of transiting exoplanets. The same technique can be used to characterise the space weather environment around exoplanets. Stellar outflows, in the form of winds and transient (bursty) mass ejections, drive the exo-space weather around exoplanets, with close-in planets experiencing harsher weather than planets orbiting further away. In this contribution, I will present our recent efforts towards characterising exo-space weather by using state-of-the-art 3D modelling of star-planet interactions with contemporaneous, multi-wavelength observations of selected planetary systems. UV spectroscopic transits, radio and optical observing campaigns, and stellar activity monitoring of host stars (optical, UV and X-rays), together with models, have allowed us to understand the space weather around HD189733b and GJ436b. Further to characterising the environment surrounding exoplanets, our studies allow us to probe atmospheric evaporation and exoplanetary magnetic fields, with on-going observing multi-wavelength campaigns underway to characterise additional systems.

Star-planet interactions
stellar activity

3. The ongoing search for radio emissions from exoplanets

Parallel Talk1512Jake Turner; Cornell University

BreezaalMon 14:40 - 15:40

Observing planetary auroral radio emission is among the most promising methods to detect exoplanetary magnetic fields, the knowledge of which will provide valuable insights into the planet's interior structure, atmospheric escape and dynamics, and habitability. Recently, we published the first possible detection of an exoplanet (τ Boo b) in the radio.In this talk, I will discuss our ongoing guaranteed Key Science Program "Exoplanets and Stars" using the NenuFAR low-frequency radio telescope in France. The main goals of the survey are to follow-up the tentative detection from τ Boo b and to search for radio waves from dozens of the most promising exoplanet candidates according to theoretical studies. NenuFAR is fully commissioned and can perform simultaneous beamformed and imaging observations. These observations will test theoretical models for the first time with a statistical sample with a high sensitivity at the predicted wavelengths. Preliminary results and the implications will be presented.

Star-planet interactions

4. Spying for SPI: First Results from HPF Observations of LOFAR detected M dwarfs

Parallel Talk1577Suvrath Mahadevan; Penn State

BreezaalMon 14:40 - 15:40

The recent detection of 19 M dwarfs in circularly polarized coherent radio emission with LOFAR opens up the intriguing possibility of star-planet interactions (SPI) as a possible source, or of the source being auroral emission from bound brown dwarfs in these systems. For a subset of these systems binary interactions (similar to RS-CVn systems) may also be the source of this emission. We will present first results from observations of these 19 radio detections using the Habitable Zone Planet Finder (HPF) on the 10m Hobby Eberly Telescope. These observations, leveraging the power of a highly stabilized precision near-infrared spectrometer, allow us to discriminate which subset of these objects are binaries and active stars, and which subset remain spectroscopically quiet, and lack any significant variability. We will also discuss continuing RV followup of the most promising detections - like the mid-M dwarf GJ 1151.

Star-planet interactions
RV, Star Planet Interactions, surveys

1. Limb asymmetries on WASP-39b: A GCM perspective

Parallel Talk201Maria Steinrueck; University of Chicago

Grote ZaalMon 14:40 - 15:40

JWST enables the detection of differences between the spectrum of the morning terminator and evening terminator in low-resolution spectra of hot Jupiters. Recently, Espinoza et al. (submitted) and Delisle et al. (submitted) reported the first such detection in transit observations of hot Jupiter WASP-39b. Both studies found a larger CO2 feature at the evening terminator. Multiple effects could potentially produce such differences, ranging from differences in temperature to gas-phase abundances to cloud coverage. Insights from 3D general circulation models (GCMs) are crucial for interpreting these observations correctly. We present results from a study comparing GCMs from multiple research groups, covering a broad range of effects that could lead to these limb asymmetries. Preliminary results show temperature differences to be a driving factor for the larger CO2 feature at the evening terminator, while disequilibrium chemistry and clouds play an important role in suppressing terminator differences at other wavelengths.

Atmospheres
atmospheric dynamics, JWST, transit spectroscopy

2. A comprehensive 3D eclipse map of the hot Jupiter WASP-17b

Parallel Talk213Daniel Valentine; University of Bristol

Grote ZaalMon 14:40 - 15:40

We present a 3D eclipse map of the hot Jupiter WASP-17b, constructed from eclipse observations spanning 1-12 microns with JWST NIRISS/SOSS, NIRSpec/G395H, and MIRI/LRS. Eclipse mapping is currently the only method of measuring 2D (longitude-latitude) emission profiles of exoplanet atmospheres. Owing to JWST’s high precision and broad wavelength coverage, this technique can now be applied spectroscopically, allowing us to probe exoplanet atmospheres at different altitudes to construct 3D maps. A wealth of information can be inferred from these maps, including heat redistribution efficiency, chemical species distribution, and winds speeds, which are vital to understanding multidimensional processes in exoplanet atmospheres. We confidently recover the hotspot offset of WASP-17b, a key diagnostic of such properties, and trace its variance across different altitudes, allowing us to contextualise these multidimensional atmospheric properties. This work forms part of the JWST Telescope Scientist Team (TST) Deep Reconnaissance of Exoplanet Atmospheres through Multi-instrument Spectroscopy (DREAMS) GTO-1353 program.

JWST Results
Eclipse Mapping, Emission spectroscopy, Exoplanet atmospheres, JWST

3. A deep dive into the hot Jupiter NGTS-10b

Parallel Talk1519Vivien Parmentier; Observatoire de la côte d'Azur

Grote ZaalMon 14:40 - 15:40

Hot Jupiters are, and will stay, the best targets for atmospheric characterisation. However, their complex 3D-structure often hinders the retrieval of accurate chemical abundances from their emission or transmission spectra. As a consequence, a thorough understanding of their 3D-thermo-chemical structure is needed.

We present the full phase curve of the hot Jupiter NGTS-10b (Teq=1400K) observed with NIRSPEC/PRISM from the optical to the infrared (0.5 to 5.5 microns). We probe the chemical composition, cloud and thermal structure of the planet with unprecedented details. We detect both dayside, nightside and transit spectra, together with wavelenght dependent phase curve offset and amplitude.

Combining 3D models and 1D radiative/convective models and retrievals we are able to fit all the available data and find evidence for horizontal quenching, a long-postulated, but yet to be observed process where the dayside chemistry is transported by the circulation, driving the nightside of the planet out of chemical equilibrium.

JWST Results
Atmospheres, Hot Jupiter, Phase curve

4. Advancing Atmospheric Retrievals of Exoplanets with JWST

Parallel Talk1625Savvas Constantinou; Institute of Astronomy, University of Cambridge

Grote ZaalMon 14:40 - 15:40

The unprecedented quality of JWST transit spectroscopy promises a transformational advance in atmospheric retrievals of exoplanets. JWST's spectral coverage and sensitivity enables precise constraints of numerous atmospheric properties and processes. We present an exhaustive atmospheric retrieval analysis of the broad-band JWST transmission spectrum the hot Saturn WASP-39b, in the 0.6-5 μm range. We present (a) atmospheric constraints from combined observations, enabled by (b) advancements in atmospheric retrieval approaches. We present a new atmospheric retrieval paradigm, combining a hierarchy of approaches to atmospheric chemistry and aerosols, including Mie scattering, and a rigorous consideration of correlated noise. We report detailed constraints on the abundances of H2O, CO2 , SO2, CO and H2S, inferring the elemental abundances of C, O and S, with important implications for its formation and migration. Our results highlight the promise of JWST exoplanet spectroscopy, underscoring the importance of sophisticated atmospheric retrieval approaches in the JWST era.

JWST Results
Atmospheric Retrievals

16:10 - 16:55 Parallel Talks 3

1. Two Sub-Neptunes and the Radius Gap: Investigating an Adolescent System Using ESPRESSO, TESS, and CHEOPS

Parallel Talk725Nataliea Lowson; University of Southern Queensland

AalmarktzaalMon 16:10 - 16:55

Understanding the formation, evolution and atmospheres of sub-Neptunes is vital, as their solid cores are similar to Earth analogues. Employing observations that include photometry from TESS and CHEOPS, we identify two transiting short period sub-Neptune planets around the bright adolescent (∼470 Myr) K-dwarf HIP113103. With a planetary radius of 1.83 R⊕, HIP113103 b resides within the sparsely populated radius gap, a hypothesised transition region between super-Earths and mini-Neptunes. The stellar age combined with the planetary radii (Rp = 2.40 R⊕ for HIP113103 c) suggests HIP113103 b has likely lost (or is still losing) its primordial atmosphere. To investigate their formation history in greater detail, we’ve gathered additional ultra-high precision spectroscopy data using ESPRESSO, with the aim of probing the atmosphere and further constraining the orbital mechanics. This system presents an exciting opportunity to discern the origins of sub-Neptune systems, and their significance in the evolution of Earth and Neptunian analogues.

RV and transits
Radius Gap, SubNeptunes, Ultrahigh Precision SpectroscopyPhotometry

2. A newly-detected population of warm sub-Neptunes orbiting bright stars confirmed with ESA/CHEOPS

Parallel Talk1048Hugh Osborn; University of Bern

AalmarktzaalMon 16:10 - 16:55

Sub-Neptune exoplanets are at the forefront of exoplanet science, especially now their atmospheres are keenly observable via JWST transmission spectroscopy. Since 2017 the dominant source of highly characterisable sub-Neptunes has been NASA/TESS. However, for the majority of the sky, TESS observes stars for only 27 days and therefore can only reliably detect planets with orbits below 20 days. I will describe how targeted observations with ESA's CHEOPS satellite of candidates producing two widely separated single transits in TESS has revealed a missing population of more than a dozen warm sub-Neptunes orbiting bright stars. The population detected by CHEOPS more than doubles the number of characterisable warm sub-Neptunes (R<4Re, P>20d, and Gmag<9.5), including key new planets in multi-planet systems for which JWST TSMs are greater than 100 such as TOI-2076c & d (P=20 & 35d), HIP9618c (P=53d), HD110067d-g (P=20-55d), and a Neptune-radius planet orbiting a naked-eye star (P=24d).

RV and transits

3. Uncovering Long-Period Transiting Exoplanets with TESS and CHEOPS

Parallel Talk1163Amy Tuson; University of Cambridge

AalmarktzaalMon 16:10 - 16:55

Long-period transiting exoplanets allow us to study planets with temperatures similar to those in our own solar system. However, due to its observing strategy, TESS is heavily biased towards the discovery of short-period planets. I am combining TESS observations with CHEOPS follow-up to increase the yield of long-period planets. I created a specialised pipeline to discover TESS “duotransits”. These are the observational signatures of long-period planets, characterised by two transits separated by a large gap, but their exact orbital periods are hidden. My pipeline discovered five new duotransits that were then observed by the CHEOPS Duotransit Program to reveal their true periods. I will present my pipeline, its discoveries and the sample of small, long-period planets being uncovered by TESS and CHEOPS, including the Neptune-mass planet TOI-5678 b and the bright multi-planet system HD 15906.

RV and transits
Pipeline development

1. JWST/NIRCam imaging of PDS 70 - A spiral accretion stream feeding PDS 70 c

Parallel Talk1423Valentin Christiaens; KU Leuven

BreezaalMon 16:10 - 16:55

Two protoplanets have been discovered within the PDS 70 protoplanetary disk using ground-based facilities. JWST now offers a unique opportunity to characterize them at wavelengths inaccessible or difficult to observe from the ground. In this contribution, I will present our results obtained in two different NIRCam filters on the iconic PDS 70 system, as part of the MIRI GTO on protoplanetary disks. I will explain the new iterative algorithm that we developed and applied to the data for unbiased imaging of circumstellar signals. I will then present and discuss our new images. Apart from the protoplanets, we identify a spiral-shaped signal which we interpret as the spiral accretion stream feeding planet c and its circumplanetary disk. I will also compare the photometry extracted for both protoplanets to existing constraints gathered from the ground. I will finally conclude on future prospects, and present preliminary JWST/NIRSpec results on this source.

JWST Results
Planet formation, Protoplanets

2. Tri-Angles: 0, 90, and180° --- Hot Jupiters' Signature Spin-Orbit Angles

Parallel Talk1589Xian-Yu Wang; Indiana University

BreezaalMon 16:10 - 16:55

Stellar obliquity offers critical insights into planetary formation, yet the underlying mechanisms responsible for it remain elusive. A notable pattern is hot Jupiters around hot stars sometimes exhibit misalignment, contrasting with their alignment around cooler stars. The inertial wave tidal realignment theory can successfully explain this pattern without involving planet engulfment. However, the predicted obliquity clustering at 0, 90, and 180° is unobserved, likely due to sample heterogeneity. Therefore, to provide a homogeneous sample, we have conducted simultaneous modeling of Rossiter-McLaughlin measurements, radial velocity data, and space-based transits for ∼100 hot-Jupiter systems. Our findings suggest, that for hot stars, stellar obliquities cluster around these specific angles, 0, 90, and 180° thereby completing the smoking gun of the inertial wave tidal dissipation theory. Moreover, simulations based on a state-of-the-art inertial tidal model suggest hot-Jupiter systems with a mix of aligned and isotropic obliquities can naturally evolve into the observed three-group pattern.

Formation and evolution
RossiterMcLaughlin effects, Stellar obliquity, Tidal realignment theory

3. Combining the atmospheric escape models of photoevaporation and core-powered mass-loss

Parallel Talk1490James Owen; Imperial College London

BreezaalMon 16:10 - 16:55

Atmospheric escape from hydrogen-dominated atmospheres can drive the evolution of close-in exoplanets. Mass-loss can sculpt the close-in exoplanet population, creating the radius-gap and Neptune desert. Currently, there are two flavors of mass-loss models: photoevaporation and core-powered mass-loss. Different energy sources power these models and cause the exoplanet population to evolve differently. Understanding which model dominates is crucial as we investigate the atmospheric composition of small planets, as they will cause the composition to evolve in distinct ways. I will show that photoevaporation and core-powered mass-loss are not distinct mechanisms and dominate different parameter space regions. Core-powered mass-loss dominates when it drives an optically thick outflow to XUV photons. Photoevaporation takes over when these photons penetrate inside the planet's Bondi radius. Coupling these new combined models with evolutionary calculations, I will show that planets experience both mass-loss flavors during their lifetime. However, the final carving of the radius-gap is by photoevaporation.

Formation and evolution
planet evolution

1. How atmospheres respond to radiative forcing?

Parallel Talk1565Jean-Michel Desert; University of Amsterdam (Netherlands)

Grote ZaalMon 16:10 - 16:55

Determining the atmospheric chemical properties of close-in transiting exoplanets, encompassing metallicity, C/O ratios, and elemental abundances, for tracing planet formation presents significant challenges. Tidally locked planets, exhibiting diverse chemistries between their scorching daysides and cold nightsides, heighten complexity, especially when comparing them across various equilibrium temperatures. This intricacy casts doubts on our ability to precisely measure the planetary global chemical abundances and metallicity, and to employ these values to unraveling a planet's history. To address these challenges, we present studies that focus on correcting for physical processes to retrieve robust planetary-scale elemental abundances. Seizing opportunities presented by unique planets (eccentric radiative forcing, mixing, etc…), we scrutinise their atmospheres using high-resolution spectroscopy and JWST, in order to disentangle the interconnected processes occuring. These studies shed light on chemical determination and on revealing robust parameters aim at enhancing our understanding of the formation and evolution of exoplanets.

Atmospheres
Atmospheric chemistry, Elemental abundances

2. JWST NIRSpec/G395H Phase-curve and Eclipse Maps of WASP-43b

Parallel Talk831Ryan Challener; Cornell University

Grote ZaalMon 16:10 - 16:55

Hot Jupiter atmospheres contain significant spatial variations in

temperature and composition due to the extreme difference in radiation

environments between their day- and nightsides. With JWST, we now have

the precision to measure these latitudinal and longitudinal spatial

variations using eclipse mapping. Here, we present a JWST

NIRSpec/G395H phase-curve observation of the benchmark hot Jupiter

WASP-43b. We show band-integrated, short-wave, and long-wave

brightness temperature maps of the entire planet, including

measurement of the dayside eastward hotspot offset, the day-night

temperature contrast, and resulting constraints on atmospheric

dynamics. We discuss the potential of a non-equatorial hotspot offset

and the implications on atmospheric properties. Furthermore, we

compare our data and retrieved maps with general circulation model

predictions to understand underlying physical processes, like heat

redistribution and cloud formation. Finally, we discuss early results

for three-dimensional spectroscopic eclipse mapping of this planet.

JWST Results
Eclipse Mapping

3. Hot Jupiters comparative exoplanetology with JWST

Parallel Talk628Qiao Xue; University of Chicago

Grote ZaalMon 16:10 - 16:55

I will present results from a large JWST GTO program focused on measuring atmospheric metallicities and carbon-to-oxygen ratios for a sample of canonical hot Jupiters(HD 149026b, HD 209458b, etc.). These two parameters are fundamental tracers of planet formation but have been challenging to determine accurately using previous facilities. Our data have enabled the first JWST comparative planetology results and a new, high-precision view of long sought-after statistical trends in these parameters. Using simple, model-independent comparisons of spectra, we have shown conclusively that hot Jupiters exhibit a surprising diversity in their atmospheric compositions. Detailed retrieval modeling provides support for these findings, indicating that the mass-metallicity relation for hot Jupiters is highly scattered and that their carbon-to-oxygen ratios may be exceptionally low. Ultimately, the results indicate that a large survey of exoplanets is needed to capitalize on the promise of using atmospheric compositions to inform how planets form and evolve.

JWST Results
Hot Jupiter, JWST

17:05 - 17:50 Parallel Talks 4

1. First results on the CRIRES+ RV search for planets around low-mass stars and brown dwarfs

Parallel Talk1179Evangelos Nagel; Georg-August-Universität Göttingen

AalmarktzaalMon 17:05 - 17:50

CRIRES+ is a state-of-the-art high-resolution spectrograph installed at the VLT. As the search for super-Earths in the habitable zone of low-mass stars is one of the main science drivers, CRIRES+ is equipped with a novel infrared absorption gas-cell with multi-species gas fillings to provide an RV precision close to 3 m/s in the K-band. The CRIRES+ consortium has launched an RV search program targeting faint and red spectral types, particularly late M and brown dwarfs (BD). Our program explores the uncharted mass territory of BD planet hosts with companions down to Neptune masses in short periods, and thus give new insights into planet formation mechanisms around sub-stellar objects. In this talk, I will showcase the first mass measurement obtained with CRIRES+, of a Mercury-like planet around an M dwarf (M5.0), and highlight the results of the RV search for planets around BDs obtained during the first year of the program.

RV and transits
Brown dwarfs, Lowmass stars, Radial velocity

2. Splendidly Synchronized: Six Sub-Neptunes Spinning a Shiny Star

Parallel Talk1462Rafael Luque; University of Chicago

AalmarktzaalMon 17:05 - 17:50

HD110067 is a K-type dwarf with six transiting sub-Neptunes orbiting in a long chain of orbital resonances. The discovery, recently published in Nature, has brought a lot of attention from the community and the general public. In this talk, we will present the latest follow-up observations of the system since its last observability window in spring 2022. Confirmed orbits of planets e and g using CHEOPS, extensive RV monitoring with RV instruments leading to improved masses, transit-timing variation analyses, refined stellar properties, and, hopefully, confirmation regarding future observations with JWST. The combination of star's brightness, number of planets, planet type, and orbital configuration makes this system one of the most promising laboratories to test theories of planet formation and gain insight into the nature of sub-Neptune planets.

RV and transits
discovery, planet formation and evolution

3. New giant planets orbiting late-type M dwarfs: system architecture at long orbital distances0

Parallel Talk1292Juan Carlos Morales; Institut of Space Sciences (ICE, CSIC)

AalmarktzaalMon 17:05 - 17:50

Exoplanet formation models predict that rocky planets are more abundant than gas giants around all types of stars. This is especially the case around late-type stars. Nevertheless, radial velocity surveys have already unveiled the existence of several Jupiter-like planets orbiting very low-mass stars in the past recent years (e.g. Morales et al. 2019, Quirrenbach et al. 2022). Such discoveries challenge the pebble accretion planetary formation models, and favors other mechanisms such as the formation by disk instability at the outskirts of protoplanetary disks. CARMENES, a survey to look for exoplanets around low-mass stars that came into operation in 2016, is discovering a number of such long period gas giants around low-mass stars, which were until now the sweet spot of microlensing surveys. In this talk, I will review the current status of such planetary systems and present several candidate planets discovered by the CARMENES spectrograph.

RV and transits
Radial velocity, surveys

1. A fading radius valley towards M-dwarfs, a density valley across stellar types

Parallel Talk1062Julia Venturini; Geneva Observatory

BreezaalMon 17:05 - 17:50

The radius valley separating super-Earths from mini-Neptunes is a fundamental benchmark for theories of planet formation and evolution. The valley’s location depends on stellar mass, planet period, and stellar age. Here, we build from our previous pebble-based formation model, which, combined with photoevaporation after disc dispersal, unveiled the radius valley as a separator between dry- and water-worlds. We run a large parameter study for a wide range of stellar masses (0.1 to 1.5 Msun), and find a slope for the location of the radius valley as a function of stellar mass and orbital period which is in excellent agreement with observations. Also as reported by observations, we find that the radius valley fades towards M-dwarfs, due to the effects of orbital migration and water condensation. Instead, when analysing the valley in terms of mean density (normalised by Earth's composition), we find a persistent density valley across all stellar types.

Demographics & Architectures
Planet evolution models, Planet formation models

2. Shallower radius valley around low-mass hosts provides evidence for icy planets or collisions

Parallel Talk1248Cynthia S. K. Ho; University College London

BreezaalMon 17:05 - 17:50

The characteristics of the radius valley (i.e. an observed lack of planets between 1.5-2 Earth radii) provide insights into planet formation and evolution. We present a novel view of the radius valley, by refitting the transits of over 500 planets and updating their planetary parameters homogeneously using Kepler 1-minute short cadence data, the vast majority of which have not been previously analysed in this way. With the updated planetary parameters, we find a deeper FGK radius valley compared to several other observations, suggesting that planets are likely to have a more homogeneous core composition at formation. We also observe that the radius valley becomes shallower towards lower mass M-dwarfs, and upon rigorous comparison, we find that these observations are inconsistent with theoretical models of photoevaporation, highlighting evidence for icy planets or collision events for low-mass stars.

Demographics & Architectures
Kepler, transits

3. The Effect of Galactic Kinematics on Planetary System Architectures

Parallel Talk1291Scarlett E Royle; Astrophysics Research Institute, Liverpool John Moores University

BreezaalMon 17:05 - 17:50

Recent studies reveal the role of stellar position-velocity clustering in sculpting planetary system architectures [1,2,3,4]. Notably, over-dense phase-space environments preferentially host systems with short-period planets, including hot Jupiters [1,4]. There is an ongoing debate over the source of this correlation, with the most prominent theories being (i) that galactic dynamical perturbations induce inward migration [4], or (ii) a relationship between hot Jupiter occurrence and host star age [5,6].With an enriched dataset from TESS and Gaia DR3, incorporating precise stellar parameters from the California Kepler Survey [7] and SWEET-Cat [8], and by implementing multivariate matching methods [e.g 9], our improved analysis aims to untangle dependencies on host star properties, such as age.In this presentation, I will re-examine the connection between planetary system architectures and stellar phase-space clustering. I will explore whether trends result from galactic perturbations, correlations with stellar age, or an interplay of these factors.

Demographics & Architectures
galaxies: interactions, Hot Jupiters, Planetary systems, stars: kinematics and dynamics

1. The 2.5 to 25-micron transmission spectrum of HD 189733b with JWST NIRCam and MIRI MRS

Parallel Talk1009Luis Welbanks; Arizona State University

Grote ZaalMon 17:05 - 17:50

As the closest transiting hot Jupiter to Earth, HD 189733b has been the benchmark planet for atmospheric characterization. It has also been the anchor point for much of our theoretical understanding of exoplanet atmospheres from composition, chemistry, and aerosols to atmospheric dynamics, escape, and modeling techniques. We observed the transmission spectrum of this archetype hot Jupiter from 2.5 to 25 microns in transmission with JWST NIRCam and MIRI MRS. We detected robust features of H2O, CO2, CO, H2S, and the lack of CH4. The bulk atmospheric composition is constrained to be 3-5 times stellar in metallicity with a low (<0.2) carbon-to-oxygen ratio. This is the sole transiting exoplanet observed using the MIRI MRS, which is the only JWST instrument capable of delivering spectral data beyond 12 microns. The wide wavelength coverage spectrum offers uniquely new insights into the cloud composition and particle sizes.

JWST Results
Clouds

2. Cloudy Mornings on WASP-107b: Panchromatic limb-asymmetry shows morning-to-evening temperature, SO2, and cloud variations

Parallel Talk1132Matthew Murphy; Steward Observatory, University of Arizona

Grote ZaalMon 17:05 - 17:50

Exoplanet atmospheres are not homogeneous. For example, day-to-night asymmetries in atmospheric properties are well known on hot exoplanets. With the unprecedented precision of JWST, probing morning-to-evening limb-asymmetries in transit is now possible too. Limb-asymmetry provides a new window into the three-dimensionality of atmospheres, offering a direct probe of how temperature, composition, and cloud properties vary between a planet’s morning and evening terminators. In this talk, I will present measurements of a panchromatic limb-asymmetry signal on WASP-107b using JWST/NIRCam and MIRI from 2 - 12 microns. Our results show changes in both the atmospheric scale height and strength of molecular absorption features. In particular, these data show clear evidence for the predicted nightside chemical production of SO2, and creation of clouds on the nightside. I will discuss how these results provide new insights for modeling the 3D dynamics and chemistry of exoplanet atmospheres, and prospects for future limb-asymmetry observations using JWST.

JWST Results
Clouds, Limb asymmetry, SO2, Transmission spectroscopy

3. WASP-121b Under the Watch of JWST: How 3D Models Compare to its Spectroscopic Phase Curve

Parallel Talk492Robert Frazier; University of Michigan

Grote ZaalMon 17:05 - 17:50

Ultrahot Jupiters present extreme physics and dynamics not found in the solar system. Magnetic drag disrupts the atmospheric circulation, clouds are confined to the nightside, and many molecules dissociate on the dayside. Spectroscopic phase curves let us measure these spatially inhomogeneous features. However, phase curves with Hubble were limited to looking at a narrow wavelength range and its observations of WASP-121b, a well known ultrahot Jupiter, could not confirm the presence of nightside clouds. JWST presents the ability to measure spectroscopic phase curves over a broad wavelength range, allowing us to observe previously inaccessible features. I will present how new phase curves of WASP-121b from JWST’s NIRISS instrument compare to cutting-edge 3D models that uniquely account for the effects of both magnetic fields and clouds in ultrahot Jupiters. This analysis serves as a guide for how complex atmospheric features will present in JWST spectroscopic phase curves.

Atmospheres
3DModels, JWST, Phase Curves

Tuesday 18 June 2024

08:30 - 17:50 Poster round 2

20 years of CORALIE RVs measurements: the outer companions of Hot Jupiters.

Poster906Léna PARC; University of Geneva

Poster AreaTue 08:30 - 17:50

Hot Jupiters were the first exoplanets to be discovered around main sequence stars and astonished us with their close-in orbits. They are a prime example of how exoplanets have challenged our knowledge of how planetary systems form and evolve. More than twenty years after the discovery of the first hot Jupiter, there is no consensus on their predominant origin channel. Three classes of hot Jupiter creation hypotheses have been proposed: in situ formation, disk migration, and high-eccentricity tidal migration. We are monitoring with CORALIE spectrograph since the early 2000’s a few tens of Hot Jupiters looking for outer companions in order to better understand their formation and evolution mechanism. We present here results of this exceptional long-term radial velocity monitoring dataset that allowed us the characterization of several systems, enabling us to better understand the interactions between the Hot-Jupiter and their external companion.

Demographics & Architectures
Dynamical interactions, Hot Jupiters, Longterm RV followup, Outer companion

3D Simulations of Exoplanetary Atmosphere Escape

Poster636Fabienne Nail; Univsersity of Amsterdam

Poster AreaTue 08:30 - 17:50

This talk delves into exoplanetary atmospheres via 3D hydrodynamic simulations, concentrating on escaping atmospheres identified through transmission spectroscopy. These escaping atmospheres, spanning up to hundreds of planetary radii, prominently feature metastable helium as a vital tracer. Notably, a substantial fraction of high-resolution helium line observations at 1083 nm exhibit a blueshift, suggesting a day-to-night side flow within the evaporating atmospheres of short-period gas giants. Moreover, recent observations of HAT-P-67b unveiled an unexpected revelation—only a distinct leading arm of the outflow was detected. Our models successfully replicate these observed phenomena, offering insights into the complex dynamics of exoplanetary atmospheres.

Atmospheres
helium observations

A formally motivated retrieval framework applied to the high resolution transmission spectrum of HD189733b

Poster794Doriann Blain; Max-Planck-Institut für Astronomie

Poster AreaTue 08:30 - 17:50

Ground-based high-resolution spectra provide a powerful tool for characterising exoplanet atmospheres. However, they are greatly hampered by the dominating telluric and stellar lines, which need to be removed prior to any analysis. Such removal techniques deform the spectrum, hence a key point is to account for this process in the forward models used in retrievals.

We will show the results of our Bayesian analysis (using PyMultiNest) on a high-resolution (resolving power of ~80,000) near infrared (0.96 to 1.71 µm) CARMENES transit data of HD 189733 b, including estimations of the planet's molecular abundances, temperature, as well as some kinematic properties. We will also briefly introduce the new and robust atmospheric retrieval framework we developed to obtain these results. This framework has been implemented in the atmospheric modelling software petitRADTRANS.

RV and transits
Atmospheres, Highresolution

A hot sub-Saturn in the middle of the Neptunian desert

Poster687Ilaria Carleo; IAC

Poster AreaTue 08:30 - 17:50

The Neptune desert is a region with a lack of short-period Neptune-sized planets observed in the sample of exoplanets discovered so far. This desert holds significant importance in the context of planetary formation and evolution theories. The lower limit of the desert can be due to photoevaporation, a process more effective in decreasing the size of close-in planets, while the might be determined by the fact that only the most massive planets can undergo tidal circularization in the closest orbits following high-eccentricity migration.

We present the discovery of a hot sub-Saturn exoplanet orbiting a G-type star. This planet, with its radius of 6 Earth radii, mass of 54 Earth masses and short orbital period of 1.56 days, lies in the middle of the Neptune desert. We present the characteristics of this system and the possible scenarios for its formation and evolution in the Neptune desert.

RV and transits

A new metric for assessing planetary surface habitability

Poster945Hannah Woodward; Birkbeck, University of London

Poster AreaTue 08:30 - 17:50

Planetary surface habitability has so far been, in the main, considered in its entirety. The increasing popularity of 3-D modelling studies of planetary climate has highlighted the need for a new measure of surface habitability. Combining known thermal limits of Earth-based life with surface water fluxes, we introduce such a measure which can be calculated from the climatological output from general circulation model simulations. In particular, we pay attention to not only 'complex' life, but additionally the temperature limits of microbial and extremophilic life which have been vital to the generation of Earth's own biosignatures. This new metric will be validated on Earth using ERA5 reanalysis data along with multiple datasets representing Earth-based life.

Habitability
climate models, limits of life

A pair of massive planets around a Sun-like star from the WINE survey

Poster915Jan Eberhardt; Max-Planck-Institute for Astronomy

Poster AreaTue 08:30 - 17:50

We present the discovery and orbital characterization of a pair of warm massive exoplanets orbiting the Sun-like star TOI-6695 (TIC118339710). These planets were detected by the TESS mission as two single-transit events, one for each planet. We validated our findings through the Warm gIaNts with tEss (WINE) survey, which systematically characterizes warm massive exoplanets with orbital periods between 10 and 300 days identified from TESS photometric data. We conducted a radial velocity follow-up using HARPS, FEROS, and CHIRON, which reveals that the inner planet has a mass of 0.31 Mjup, similar to Saturn, and an orbital period of about 80 days. The second companion is consistent with a Jovian exoplanet with a mass of 1.23 Mjup, and an orbital period of about 250 days. This system provides new insights into the properties of warm massive planets, expanding our knowledge of planetary formation and evolution.

RV and transits
Dynamics

A physical cloud model for atmosphere retrieval

Poster570Helong Huang; Tsinghua University

Poster AreaTue 08:30 - 17:50

With the launch of JWST, we are embracing an era of precise measurement of exoplanet atmosphere’s transmission and emission spectrum. In interpreting these data, the presence of clouds plays a crucial role. However, in retrieval methods, clouds are typically imposed by parameters such as cloud deck pressure, mixing ratio. Here, we have developed a streamlined cloud model that calculates clouds from elementary physical and chemical principles. The model includes particle transport, growth, and can cope with an arbitrary large number of condensate species. The general setup of our model allows computation of cloud structure in hot-Jupiters, super-Earths and self-luminous planets. For hot-Jupiter planets, we find layers of MgSiO3, Fe and Al2O3 clouds, recovering the characteristics of physically more complex models. With the computational cost on the order of seconds on a regular PC, our cloud model can be embedded into the majority of existing atmosphere retrieval codes.

Atmospheres
Cloud model

A planetary-mass candidate around a young solar-mass binary

Poster683Pengyu Liu; Leiden University

Poster AreaTue 08:30 - 17:50

Direct imaging of exoplanets is mainly targeted at single stars. However, a large proportion of stars are in binary or multiple systems. Stellar multiplicity can affect planet formation and orbital stability. We will present a planet candidate around a binary system with the primary star of a young Sun analogue, YSES 3. Photometric analysis indicates it is a likely planetary-mass object. We develop a method to perform precise astrometric analysis of companions around a tight binary. Our five-year observations rule out the possibility that it is a static background star. But its strange motion makes its origin obscure. Its motion is too large for a bound companion at such a wide separation (~725 AU), while no other background stars in the field of view resemble its motion, making it still weird even as a free-floating object. We will discuss its possible origins.

Direct Imaging and Interferometry
binary stars, direct imaging

A reanalysis of the spectral characteristics of the ultra-cool dwarf TRAPPIST-1

Poster660Fatemeh Davoudi; Unversity of Liege

Poster AreaTue 08:30 - 17:50

A comprehensive infrared spectroscopic study of the TRAPPIST-1 star is a crucial step towards the detailed study of its planets. Earth's atmosphere limits IR observations, but we overcome this challenge by utilising publicly available spectroscopic data from the NIRISS and NIRSpec instruments aboard the JWST telescope. This approach enabled us to derive the 0.6–5 micron spectral energy distribution for this M dwarf (Figure 1) and to provide robust constraints on the bolometric flux, radius, mass, and metallicity of the star. Our study also utilised the NIRISS spectrum for the study of photospheric indices (Figure 2) and assessed Ca II indices and other activity indicators, including Hα emission, establishing new Hα strength bounds and revealing a moderate level of stellar activity. We utilise photospheric modelling with theoretical and JWST spectra to constrain stellar surface heterogeneities, which is important for distinguishing planetary signals from potential stellar contamination in transit transmission spectroscopy studies.

JWST Results
JWST, TRAPPIST1

Analyzing Opacity Model Sensitivity in JWST Transmission and Emission Spectra

Poster700Aaron Householder; Massachusetts Institute of Technology

Poster AreaTue 08:30 - 17:50

The recent launch of the James Webb Space Telescope (JWST) promises to revolutionize our understanding of exoplanetary atmospheres. With JWST, we now have the capability to detect and quantify molecular abundances in exoplanet atmospheres with unprecedented precision. However, unlocking the full potential of JWST's observations is not without challenges. For example, the initial observations from JWST Cycle 1 have highlighted certain inadequacies in our modeling approaches (see e.g. Moran et al. 2023). Here, we explore the implications of opacity model selection on JWST transmission and emission spectroscopy observations. We find that emission spectroscopy with JWST is particularly at risk of biased molecular abundances, as it probes deeper atmospheric layers that are associated with pressure regimes at which the main limitations of opacity models arise. To mitigate these challenges, we advocate for the generation of new state-of-the-art opacity data, which will require computationally expensive quantum calculations.

JWST Results
Atmoshperes, JWST, Opacity models

Ask Gaia: The first chatbot for astrophysics

Poster885Simon Albrecht; Aarhus University

Poster AreaTue 08:30 - 17:50

Large Language Models (LLMs) have become extremely popular over past year. Researchers have experimented with using an LLM-powered chatbot (usually Chat-GPT) as an “assistant” to help them understand existing work and even discuss new research ideas. However, a pure LLM chatbot tends to make plausible sounding but unsupported statements, and cite non-existing papers, which severely limits its usefulness.Retrieval Augmented Generation (RAG) restricts an LLM chatbot to using only a particular body of literature to answer questions. The answer is extracted from retrieved text, and the sources (papers, sections, paragraphs) are listed. Therefore a RAG chatbot can greatly support literature search and research more generally.To demonstrate the potential of RAG for astrophysics, we developed and validated a RAG chatbot using Gaia manuals and science papers. Gaia data products are complex and will remain relevant for decades, making it important that helpful information remains easily accessible for astrophysicists.

Other
Artificial Intelligence, Gaia, Retrieval Augmented Generation (RAG)

Astrometric jitter due to magnetic activity for Sun-like stars

Poster939Sowmya Krishnamurthy; Max Planck Institute for Solar System Research

Poster AreaTue 08:30 - 17:50

The astrometric detections of exoplanets by missions such as Gaia and Small-JASMINE rely on the measurement of tiny changes in the positions of stars i.e. astrometric jitter, arising from the gravitational interaction with their planetary companions. Another source of astrometric jitter is the stellar magnetic activity which can influence detection and characterization of Earth-mass planets using astrometric measurements. In this context, we explore the conditions under which the magnetic activity-induced jitter becomes comparable to the planet-induced jitter. In particular, we investigate the dependence of magnetic jitter on inclination of the stellar rotation axis, metallicity, configuration of magnetic features, and rotation rate. We show that, depending on the inclination and metallicity, the jitter for stars with solar-like magnetic activity becomes comparable to the jitter produced by an Earth-mass planet at 1 AU. We find that for certain configurations of magnetic features, the activity-induced jitter reaches levels detectable by Gaia.

Microlensing and Astrometry
Astrometric jitter

Atmospheres of ultra-hot rocky exoplanets as windows into their interior

Poster869Fabian Seidler; ETH Zürich

Poster AreaTue 08:30 - 17:50

The mass and radius of a (rocky) exoplanet place only first-order constraints on its chemical composition due to degeneracies in interior models. This is particularly true for oxygen, whose relative abundance governs how iron partitions between the mantle and core. However, the bulk oxygen abundance of a (terrestrial) planet must be lower than that of its host star, as O is depleted during planetary formation. The atmospheres of ultra-hot rocky exoplanets present unique opportunities to study their interior and geochemistry. Such planets likely harbour lava oceans which dictate the nature and chemistry of their overlying atmospheres. In this study, we present models to retrieve atmospheric chemistry, structure and spectra in a thermodynamically self-consistent way, allowing us to make inferences about the composition of rocky exoplanet interiors, including its oxygen abundance. We put our findings in context of planetary evolution, and explain how these hypotheses can be tested with JWST observations.

Atmospheres
atmosphereinterior interaction, hot rocky exoplanets, lava planets

Atmospheric variability in an exoplanet.

Poster568Quentin Changeat; European Space Agency - STScI

Poster AreaTue 08:30 - 17:50

Observations of exoplanet atmospheres have not yet been able to infer weather patterns. This is typically due to the low signatures from past instruments and the lack of repeated observations. In a recent study, we utilize repeated observations of an ultra-hot Jupiter to study the variability of its atmosphere. Crucially, we detect significant differences between the observations. The observed variability manifests as: i) shift of the 'hotspot' offset between two phase-curves and ii) varying spectral signatures in the transits and eclipses. We combined the constraints infered from modern atmospheric retrievals to perform high-resolution dynamics calculations taylored to simulate the atmosphere of this planet, showing that the observed variability is consistent with quasi-periodic weather patterns.

Atmospheres
data analysis, exoplanet atmosphere, variability

Chaotic Type I Migration in Turbulent Discs

Poster704Yinhao Wu; University of Leicester

Poster AreaTue 08:30 - 17:50

We demonstrate that elevated levels of turbulence induce highly stochastic migration torques on low-mass companions embedded in these discs. This scenario applies to planets migrating within gravito-turbulent regions of protoplanetary discs as well as stars and black holes embedded in the outskirts of AGN accretion discs. When the turbulence level is low, linear Lindblad torques persists in the background of stochastic forces and its accumulative effect still dominate over relatively long timescales. However, in the presence of very stronger turbulence, classical flow patterns around the companion embedded in the disc are disrupted, leading to significant deviations from the expectations of classical Type I migration theory over arbitrarily long timescales. Our findings suggest that the stochastic nature of turbulent migration can prevent low-mass companions from monotonically settling into universal migration traps within the traditional laminar disc framework, thus reducing the frequency of three-body interactions and hierarchical mergers compared to previously expected.

Star-planet interactions
Hydrodynamics, planet migration, planetdisk interaction

Characterising young transiting exoplanet host stars within the GAPS project

Poster674Simone Filomeno; Università degli Studi di Roma 'Tor Vergata'

Poster AreaTue 08:30 - 17:50

It is currently known that planets form within a few million years from star formation, consequently, stars and planets are interconnected. Precise and homogeneous measurements of stellar parameters and abundances are essential to accurately characterise the properties of planets belonging to the system and to understand the correlations between their properties and those of the planetary environment. Since there are not yet many systematic studies on young stars (<1Gyr), this work is aimed at characterising a sample of young transiting planet host stars, observed as part of the Global Architecture of Planetary System program focused on young objects (GAPS-YO). Stellar parameters and elemental abundances of 18 elements (light, iron-peak, alpha-, s-process...) were homogeneously and accurately derived and then discussed in the context of planetary formation. The results will help to clarify how stellar environment affects the planetary formation and evolution process, and the relationship between stars and young planets.

Star-planet interactions
spectroscopy, stellar abundances, stellar atmospheres, stellar parameters

Circumbinary planet occurrence rates and detection limits

Poster750Matthew Standing; European Space Agency

Poster AreaTue 08:30 - 17:50

Circumbinary planets, those which orbit both stars of a binary system, challenge our understanding of planet formation and orbital evolution. Transit missions have discovered 14 circumbinary planets, and future missions such as PLATO will likely more than double their number. Radial velocities will be required to confirm these detections. However, despite the radial velocity method being the most established technique for planet detection, only recently has it become possible to detect circumbinary planets using radial velocity measurements.I will present a radial velocity discovery of a second circumbinary planet in the TOI-1338/BEBOP-1 system, the second multiplanetary circumbinary system ever discovered as part of the Binaries Escorted By Orbiting Planets (BEBOP) survey. I will also present an efficient method to calculate detection limits for radial velocity datasets with minimal assumptions, preliminary occurrence rates from the BEBOP and DMPP surveys, and describe plans for detection of circumbinary planets with PLATO.

RV and transits
Circumbinary planets, Detection limits, Radial velocity

Clouds and Clarity: Revisiting Atmospheric Feature Trends in Neptune-size Exoplanets

Poster686Jonathan Brande; University of Kansas

Poster AreaTue 08:30 - 17:50

Over the last decade, precise exoplanet transmission spectroscopy has revealed the atmospheres of dozens of exoplanets, driven largely by observatories like the Hubble Space Telescope. One major discovery has been the ubiquity of atmospheric aerosols, often blocking access to exoplanet chemical inventories. We present an analysis of a physically homogenous sample of 15 exo-Neptune transmission spectra across a wide range of temperatures (200-1000 K). Using condensation cloud and hydrocarbon haze models, we find the exo-Neptune population is best described by very low cloud sedimentation efficiency Fsed=0.01 and high metallicity (100x Solar). There is an intrinsic scatter of 0.5 scale height, perhaps evidence of stochasticity in these planets’ formation processes. With JWST’s greater wavelength sensitivity, future work should focus on colder exo-Neptunes given their comparative rarity, clearer atmospheres, and the need to distinguish between the “super-puffs” and more typical gas-dominated planets

Atmospheres
Atmospheric Aerosols, Exoplanet Transit Spectra

Cross-correlations and JWST: an alternate route towards atmospheric composition

Poster744Emma Esparza-Borges; Instituto de Astrofísica de Canarias

Poster AreaTue 08:30 - 17:50

JWST observed for the first time the hot-Jupiter WASP-39b on July 2022 as part of the JWST Transiting Exoplanet Community Early Release Science (JTEC ERS) Program. Since then, several atomic and molecular species (e.g Na, H2O, CO2, SO2) have been detected in its transmission spectrum. In the initial analysis, CO was detected using NIRSpec PRISM transit observation. However, this detection could not be confidently confirmed in the initial analysis of the higher resolution observations with NIRSpec G395H disperser. In this context, we performed an alternative analysis of NIRSpec G395H data using cross-correlation techniques, which confirmed the detection of CO in the atmosphere of WASP-39b. In this talk we present our cross-correlation approach as a prospective tool to study atmospheric compositions with JWST and we show our latest results on more molecules, including detections of H2O and CO2.

JWST Results
Atmospheres, Crosscorrelations, Transmission spectroscopy

Design and on-sky performance of the high-contrast imaging modes of the new VLT/ERIS instrument

Poster931Jean Hayoz; ETH Zürich

Poster AreaTue 08:30 - 17:50

ERIS is the new near-infrared adaptive-optics assisted instrument at the VLT. Beside its spectroscopic and regular imaging modes, ERIS offers three high-contrast imaging modes: (i) two vortex coronagraphs operating in the L and M bands, with a discovery space starting at ~1/D and a contrast performance of ~12.5mag at 1” measured on-sky, (ii) a gvAPP coronagraph operating in the KLM narrowband filters of ERIS at 3-9/D with a contrast performance of ~9mag at 0.5”, and (iii) three sparse aperture masks providing non-redundant interferometric imaging, reaching an on-sky contrast of ~6mag at 50mas in K-band. The high performance of these HCI modes will enable observations of Jupiter-mass planets in young, nearby systems.

In this contribution, we review the design of the three HCI modes of ERIS, present their performance in terms of contrast and sensitivity based on data obtained during commissioning, and discuss their scientific discovery space.

Direct Imaging and Interferometry
Instrument

Direct Simulation Monte Carlo modelling of exoplanetary atmospheres

Poster792Leander Schlarmann; University of Bern

Poster AreaTue 08:30 - 17:50

In this study, we use the Direct Simulation Monte Carlo (DSMC) method [1] to model exoplanetary atmospheres. First, we used the DSMC model [2] to simulate the atmospheres of the icy Galilean satellites Europa, Ganymede, and Callisto and locate the collisional parts in these atmospheres [3, 4]. With Juno, JUICE, and Europa Clipper, the atmosphere of these moons will be studied extensively, which gives us the opportunity to compare the results of our model. Second, we extend the application to exoplanetary atmospheres, which will help us improve our understanding of how the observable part of exoplanetary atmospheres is connected to the underlying planetary layers. The DSMC method is ideal for modelling atmospheres of exoplanets with extensive magma oceans on their surface, such as 55 Cancri e, where the atmosphere originates from the sublimation of surface material. Therefore, we will investigate the collisional atmosphere of these lava worlds.

Atmospheres
DSMC, Lava worlds

Disequilibrium chemistry modelling indicates a carbon-rich atmosphere on WASP-69b

Poster540Nidhi Bangera; Space Research Institute, Austrian Academy of Sciences

Poster AreaTue 08:30 - 17:50

Exoplanet atmospheres can be driven out of thermochemical equilibrium by processes such as the vertical mixing of gas and photochemistry driven by stellar radiation. The recent detection of photochemically produced SO2 in the atmosphere of WASP-39b highlights the importance of modeling and understanding these disequilibrium processes in interpreting exoplanet observations. In this study, we use a 1D photochemical-kinetic model to simulate the atmosphere of the warm-giant planet WASP-69b in support of GIANO-B high-resolution transmission spectroscopy observations. We carry out a parameter study involving carbon-to-oxygen ratios, temperature-pressure profiles, and eddy diffusion profiles in our disequilibrium models for the five molecules detected in its atmosphere, including the photochemical product C2H2. We find that C2H2 is preferentially produced in carbon-rich, high-temperature environments. Fitting our results to observations of WASP-69b suggest that it has a carbon-rich atmosphere, consistent with a C/O=2.

Atmospheres
Chemical disequilibrium, eddy diffusion, photochemistry

Does atmospheric composition actually trace formation? Observing aligned vs misaligned hot Jupiters as a testbed

Poster890Eva-Maria Ahrer; Max Planck Institute for Astronomy

Poster AreaTue 08:30 - 17:50

Determining a single planet’s formation history from its atmospheric composition is challenging due to the uncertainties regarding protoplanetary disc composition and planetary evolution. We are undertaking a survey with JWST that is focussing on planets that we know underwent different evolutionary histories due to their different orbital alignments. It is believed that aligned planets are the outcome of disc migration, while misaligned ones arise from high-eccentricity migration. This dichotomy leads to differences in the material they accrete during their evolution, which in turn should lead to differences in their atmospheric C/O. By comparing the relative composition of three aligned and three misaligned hot Jupiters, we will test if C/O depends on planet migration and thus if it can be used to make robust inferences about formation. I will give an overview of our program (GO3838), present new predictions from disc chemistry models, and share the first transmission spectra.

Atmospheres
Exoplanet atmospheres, Exoplanet formation, Exoplanet migration

Dynamics and Origins of the Near-resonant Kepler Planets

Poster843Max Goldberg; California Institute of Technology

Poster AreaTue 08:30 - 17:50

The environments in which small planets accrete are difficult to probe directly. However, pairs of planets that are close to orbital resonances provide a window into the inner regions of protoplanetary disks, as they preserve the conditions of their formation and early evolution of their orbital architectures. We present a novel approach toward quantifying transit timing variations within multiplanetary systems and examine the near-resonant dynamics of over 100 planet pairs detected by Kepler. Using an integrable model for first-order resonances, we find a clear transition from libration to circulation of the resonant angle at a period ratio of ≈0.6% wide of exact resonance, demonstrating that they systematically lie far from the resonant forced equilibrium. Cumulatively, our modeling indicates that while orbital architectures shaped by strong disk damping or tidal dissipation are inconsistent with observations, stochastic stirring by turbulent eddies in the protoplanetary disk reproduces several features of the data

Formation and evolution
Exoplanet dynamics, Orbital resonances, Transit timing variations

Eclipse Mapping of Exoplanets with Smoothness Optimised by Cross-Validation

Poster582Mark Hammond; University of Oxford

Poster AreaTue 08:30 - 17:50

Eclipse mapping allows us to fit maps of 2D thermal emission from the day-side of tidally locked exoplanets. This is the only way to access latitudinal information about these planets, which is vital for understanding their atmospheres. It has not been clear how much complexity to use when fitting these maps; low-order fitting functions fail to resolve realistic features but high-order functions overfit to noise and produce unrealistically noisy results. We present a new method to fit these maps using a smoothness regularisation parameter tuned by optimising the k-fold cross-validation score of the resulting fit. We show this produces optimal map fits for simulated data and apply our method to real observational data for HD 189733b, WASP-18b, and WASP-43b. We show no significant evidence for mapping in the first two cases, and fit a new optimised eclipse map to the last case.

Atmospheres
Eclipse Mapping, Hot Jupiters

ESA PLATO Mission: Data access and community involvement

Poster984Ana M. Heras; ESA/ESTEC

Poster AreaTue 08:30 - 17:50

ESA’s PLATO mission is designed to detect and characterise exoplanets using high-precision, long-term photometric monitoring of more than 200,000 bright stars (V < 13). The launch date is scheduled end 2026. Data products will be released to the community every three months. For targets in the statistical sample, the observation products of a given three-month observation period will be available 6 months later. For the Prime sample, that is, objects for which the ground-based follow-up is a mission deliverable, products of every three-month observation will be released 1.25 years afterwards. Additionally, scientists will be invited to apply for complementary science observing time. In this context, ESA will issue a first AO for the Guest Observer’s Programme nine months before launch. Participation in PLATO is also possible by joining the PLATO Mission Consortium and supporting its activities, and by contributing to the ground-based preparatory and follow-up observations of the PLATO targets.

Future missions/instrumentation
Demographics & Architectures, Formation and evolution, Interiors, RV and transits

Exoplanet Detection and Mass Measurements with the FOCES spectrograph at the Wendelstein Observatory

Poster889Luis Thomas; University Observatory Munich, LMU

Poster AreaTue 08:30 - 17:50

We present the FOCES spectrograph and its results from the first two observing programs. FOCES is a fiber-fed, optical, high-resolution (R 60,000) Echelle spectrograph that is installed at the 2.1m telescope on the Wendelstein Observatory in the German Alps. The main goal is to perform precise mass measurements of new exoplanet candidates. To achieve the target stability of ~ 1 m/s the spectrograph is placed inside a temperature and pressure stabilized tank (< 0.01 K and <0.1 hPa) and uses a laser-frequency comb for precise wavelength calibration.

The first two observing programs started in May 2022. One is dedicated to the detection of hot-Jupiter candidates and the exploration of the magnitude limit for FOCES. The second program aims to detect intermediate sized super-Neptunes (4 - 8 R⊕) in and around the Neptune desert. The main results are the confirmation of six new exoplanets including 4 hot-Jupiters and 2 super-Neptunes.

RV and transits
combcalibrated spectrograph, TESS followup

Explaining JWST observations of 55 Cancri e using self-consistent atmospheric models.

Poster648Mantas Zilinskas; SRON

Poster AreaTue 08:30 - 17:50

JWST NIRCam and MIRI observations of 55 Cancri e have provided compelling evidence of a volatile-rich atmosphere with clear spectral features in the emission spectrum. To explain these observations and infer the atmospheric composition, we conducted an extensive grid search of self-consistent forward models, spanning a wide range of bulk compositions with volatile and silicate enrichment scenarios. These 1-D models account for photochemistry, condensation, outgassing processes, and maintain thermal structure consistency. Our findings are compared to retrieval results, not only refining our understanding of the atmospheric composition of 55 Cancri e, but also revealing degeneracies among the best-fitting models. We discuss the potential scenarios that explain JWST observations of 55 Cancri e.

Atmospheres
55 Cancri e, Atmospheres, JWST

Exploration of possible atmospheres on TRAPPIST-1b

Poster666Alice Maurel; Institut d'Astrophysique de Paris

Poster AreaTue 08:30 - 17:50

TRAPPIST-1, with its seven temperate planets, is one of the most promising exoplanetary systems discovered to date. It has therefore been a choice target for observations during cycles 1 and 2 of JWST.So far, transit spectra appear too be contaminated – due to the stellar activity of TRAPPIST-1, the host star –, preventing us to draw conclusions about the potential atmospheres on the planets (see Lim et al. 2023). However, the thermal emission of the inner planets, TRAPPIST-1b an c, have been measured during secondary eclipses.We used the Generic PCM, a 3-Dimensional Global Climate Model (GCM) historically known as the LMD Generic GCM, to model various families of atmospheres on TRAPPIST-1b and study if some of them are compatible with the observed brightness temperatures of the planets.

Atmospheres
TRAPPIST1

Exploring beyond! Advancements in exoplanet detection in the SHINE High-Contrast Imaging survey through RSM framework

Poster958Mariam Sabalbal; Université de Liège

Poster AreaTue 08:30 - 17:50

In high contrast imaging (HCI), a novel detection algorithm for angular differential imaging (ADI) sequences has recently been introduced: Regime Switching Model (RSM, Dahlqvist et al. 2021). This detection algorithm combines the output of multiple ADI-based techniques via a regime-switching framework to generate a single detection map. The results obtained by RSM during the exoplanet imaging data challenge demonstrated enhanced ability in discerning planetary signals from bright speckles, outperforming other HCI algorithms.We employ the RSM algorithm to analyse the complete F150 sample of the SHINE survey, acquired with the SPHERE high-contrast imager at the VLT. We assess the optimal combination of the ADI-based methods for both high and low separations. In comparison with results obtained previously with standard algorithms, we observe a notable improvement in the detection limits, yielding a gain factor of 5. We identify a few new exoplanet candidates that necessitate follow-up to examine common proper motion.

Direct Imaging and Interferometry
exoplanet detection, high contrast imaging, image postprocessing

Exploring Systematic Errors in the Inferred Parameters of the Transiting Planets

Poster815Alison Duck; The Ohio State University

Poster AreaTue 08:30 - 17:50

Transiting planet systems offer a unique opportunity to measure precise masses and radii of planets and their host stars. However, relative photometry and radial velocity measurements alone only constrain the host star density, leaving a one-parameter mass-radius degeneracy. We assess the magnitude of systematic errors in the derived system parameters relative to their statistical precision due to different methods of breaking this degeneracy. We first model extant data for the typical hot Jupiter system KELT-15 using EXOFASTv2, considering four methods of breaking the stellar mass-radius degeneracy. We find systematic differences in the inferred physical parameters of the KELT-15 system, including a 6.5% (~1.8σ) difference in the stellar and planetary radii based the degeneracy-breaking method. We then evaluate the systematic errors for several systems of M-dwarfs transiting FGK host stars. Finally, we present a homogenous analysis of ~10 hot Jupiter planetary systems with secondary eclipses observed by TESS.

RV and transits
Host Stars, Systematic Uncertainties

Exploring the Mornings and Evenings of Distant Exoplanets

Poster641Nestor Espinoza; Space Telescope Science Institute

Poster AreaTue 08:30 - 17:50

One of the key open questions in gas giant atmospheric science is to understand how much their properties vary throughout their atmospheres. Understanding their 3D structures is critical particularly if the aim is to constrain planet formation pathways through atmospheric abundances: if there is not one single set of abundances to extract, there might not be a single formation pathway to constrain. Here, I will present current efforts that explore this question via morning/evening spectroscopy of exoplanets. This technique aims at studying direct spectra from the leading and trailing limbs of exoplanets during transit, allowing it to disentangle their contributions to the transit lightcurve. Using precise measurements from JWST, we will showcase the first set of measurements of this effect with real data, which showcase the opening of a new window to put tight constraints on temperatures and C/O ratios of the mornings and evenings of exoplanets.

Atmospheres
Exoplanet atmospheres, Exoplanet interiors, JWST

Fast Fractal Clouds: Aggregate Aerosols in the Virga Cloud Code

Poster716Sarah E. Moran; Lunar and Planetary Laboratory, University of Arizona

Poster AreaTue 08:30 - 17:50

We introduce a new module with the open-source Virga cloud modeling code to treat fractal aggregate aerosol particles. Previously, Virga assumed spherical aerosol particles, while substantial evidence from the Solar System suggests that fractal particles are common. Following recent advances made to extend microphysical models to non-spherical particles, we implement a simple parametrization for dynamical and optical effects of fractal particles within the existing Virga framework. We then perform a case study of the well-characterized mini-Neptune GJ 1214 b to demonstrate how our new fractal treatment affects theoretical spectra of these worlds and how these compare to existing observations, as well as how our method compares to previous fractal aggregate particle treatments. We also provide testable predictions for future observations, such as from JWST and ARIEL, to better characterize and understand potentially hazy or cloudy planetary atmospheres.

Atmospheres
hazes

First discovery by NIRPS : TOI-756c, an eccentric warm giant companion to the TESS Sub-Neptune.

Poster616Léna PARC; University of Geneva

Poster AreaTue 08:30 - 17:50

With an ambitious Guaranteed Time Observation (GTO) program spanning 725 nights over a 5-year period, NIRPS, the new NIR spectrograph installed on the 3.6m telescope in La Silla, is poised to play a pivotal role in radial velocity (RV) follow-up observations of transiting planets. Notably, it marked its debut by characterizing two planets : TOI-756 b and c. Indeed, TOI-756 b is a sub-Neptune with a 1.24 days orbital period detected by TESS and confirmed with photometry follow-up observations transiting a faint M2-star. To characterize the planetary nature of this planet by measuring its mass, we performed an RV follow-up campaign combining NIRPS/HARPS spectrographs. This campaign also revealed a non-transiting outer giant planet on an eccentric orbit, marking the first discovery of NIRPS. We present here the characterization of this system and the implications on the formation and evolution of such a rare system around an M-dwarf.

RV and transits
Detection and Characterization, NIRPS, SubNeptune, Warm eccentric giant

First SPACE Program results: a near-infrared transmission spectrum of the hot sub-Neptune HD 86226c

Poster605Kim Angelique Kahle; Max Planck Institute for Astronomy

Poster AreaTue 08:30 - 17:50

The abundant class of sub-Neptunes is a bridge between the well-studied gas giants and the mostly unexplored Earth-size planets. The Solar System lacks such a planet, reinforcing the importance of examining sub-Neptunes around other stars.

To date, only a few sub-Neptune atmospheres have been successfully characterized, many of which have muted spectral features. Whether this is caused by high mean molecular weight atmospheres, high altitude aerosols, or a different mechanism is still unknown. To explore the underlying physics and chemistry, the Hubble Space Telescope Sub-neptune Planetary Atmosphere Characterization Experiment (SPACE) probes a sample of 8 sub-Neptunes across a grid of radius and equilibrium temperature.

Here we present the first results for HD 86226c, a 2.2 Earth radius planet. With a high temperature of 1300 K, photochemical hazes are less likely to be present, making HD 86226c a promising candidate to measure the underlying atmospheric composition.

Atmospheres
Atmospheres, Individual: HD 86226c, SubNeptunes, Techniques: transmission spectroscopy

Forging planets in Fornacis

Poster688Pengyu Liu; Leiden University

Poster AreaTue 08:30 - 17:50

I will present preliminary results of a direct imaging survey of exoplanets in a nearby young open cluster, X1 Fornacis. The membership of X1 Fornacis cluster has increased rapidly in recent years. It has also been revealed to be of 30 Myr, younger than previously thought. A prominent abundance of stars with IR excess of this cluster indicates a high occurrence rate of debris disks, which is a sign of planet formation. We select 18 stars from this cluster and are granted 27 hours of SPHERE observations. We aim to search for planets with separations of 27-500 au. This survey will walk us into the planet formation of the Fornax–Horologium Association, one of the nearest young stellar populations to the Sun.

Direct Imaging and Interferometry
open cluster, planet searching, young stars

Formation of rocky exoplanets around smaller stars and their compositional diversity

Poster1651Petra Hatalova; University of Oslo

Poster AreaTue 08:30 - 17:50

Super-Earths exhibit a wide range of compositions as inferred from their mean densities. How multiple close-in super-Earths form around smaller stars is still an open issue. Several modelling studies have focused on planet formation around M dwarfs, but so far no studies have focused specifically on K dwarfs, which are of particular interest in the search for extraterrestrial life. We aimed to reproduce the known population around K dwarfs and their system characteristics. We performed numerous N-body simulations of 100 Myr of planet formation via planetesimal accretion running on GPUs. With suitable initial conditions, we managed to reproduce the main characteristics and architectures of the known systems and produce mostly long-term stable, nonresonant planetary systems. These dynamical simulations were then combined with the equilibrium condensation simulations in order to constrain the bulk compositions and core mass fractions of the planets in our systems.

Other

From Dust to exoplanetary System, Planet Formation in Dust Rings Informed by Alma Observations.

Poster681Nicolas Kaufmann; University of Bern

Poster AreaTue 08:30 - 17:50

We investigate the formation of planetary systems in pressure bumps that are informed by the ringlike structures in ALMA observations of protoplanetary disks. Our global formation simulations track the growth of the planets from the dust to the final planetary system. Our global formation model (Bern Model) [1] includes the evolution of the dust and gas in the disk, the formation of planetesimals/embryos, pebble/planetesimal and gas accretion. This allows us to investigate the nature of the planetesimal and embryo formation processes going on in these rings and explore their potential imprint on the resulting planetary systems. This study demonstrates the importance of improving our understanding of planetesimal and embryo formation in these environments as the census of these structures in protoplanetary disks continues to grow. It reveals that these processes leave a significant imprint in the expected properties of the planets we expect.

Formation and evolution
ALMA, embryo formation, planetesimal formation

Getting to know long-period giant planets with Hipparcos-Gaia astrometry

Poster596Alexander Venner; University of Southern Queensland

Poster AreaTue 08:30 - 17:50

Giant planets with orbits beyond the ice line give important insights on planet formation and evolution. However, the detection and characterisation of these planets is challenging. The recent development of Hipparcos-Gaia astrometry provides a new means for understanding these planets, through true masses for known radial velocity planets and newly discovered long-period giant planets. I will present results from my research involving Hipparcos-Gaia astrometry, including a significant planet-binary misalignment for the known extremely eccentric planet HR 5183 b, and a new giant planet with a Saturn-like orbit. I will further present preliminary results from a JWST program aimed at the direct detection of a giant planet orbiting a white dwarf motivated in part by astrometric evidence. These results enrich our understanding of giant planets on distant orbits, and contributes towards a full picture of their origins.

Microlensing and Astrometry
Astrometry

Global 3D MHD dynamo simulations of Hot-Jupiter in different evolutionary times

Poster973Albert Elias-López; Insitute of Space Sciences

Poster AreaTue 08:30 - 17:50

The anelastic approximation has now long been used to simulate the electrically conducting interior of planets to obtain somewhat similar magnetic fields. With thousands of exoplanets being discovered the field is expecting the first radio emission from planetary magnetism. Hot-Jupiters are one of the best candidates to have strong enough magnetic fields. We have used Global 3D MHD simulations under the anelastic approximation to study the gigayear evolution of the possible interior dynamos for Hot-Jupiter dynamos. The interior background state (for density, temperature and other thermodynamical variables) have been taken from the MESA's gas giant module. We first characterize the change in interior dynamo with the different dimensionless parameters that dictate their physical characteristics, i.e. Ekman number, Raileigh number and Prandtl numbers, as well as testing different boundary conditions. With appropriate parameters we then study how the magnetic field changes in strength and topology in different evolutionary times.

Interiors
Gigayear evolution, Global 3D MHD simulation, HotJupiters, Planetary dynamos

HD 22946 d: a 47-day transiting warm sub-Neptune confirmed by TESS and CHEOPS

Poster903Zoltán Garai; HUN-REN-ELTE Exoplanet Research Group

Poster AreaTue 08:30 - 17:50

HD 22946 is a bright (G = 8.13 mag) late F-type star around which three transiting planets were identified via TESS photometry, but the true orbital period of the outermost planet d was unknown until now. This planet, due to the limited observing duration of the TESS mission, produced only two transits in the photometric data, separated by a large gap, about two years, leaving many possibilities for the period. We performed photometric follow-up observations with CHEOPS to confirm the true orbital period of planet d and improve the radius precision of the planets in the system. We successfully determined the true orbital period of planet d to be 47.42489(11) days. As a warm sub-Neptune, it is very interesting because there are only a few similar confirmed exoplanets to date. Such objects are worth investigating in the near future, for example in terms of their composition and internal structure.

Demographics & Architectures
methods: observational, planets and satellites: fundamental parameters, techniques: photometric

Homogeneous and precise characterization of exoplanet hosting stars within the Ariel and GAPS projects

Poster739Katia Biazzo; INAF-Astronomical Observatory of Rome

Poster AreaTue 08:30 - 17:50

The wonderful progress made during the last years in the search for exoplanets has led to the discovery of a remarkable diversity of planetary systems population. The properties of the exoplanets and planetary systems strongly depend on the properties of the host stars: it is now clear that 'to know the planet' with accuracy and precision it is necessary 'to know the star' as accurately and precisely as possible. In this talk, I will present the efforts done within the Ariel and GAPS projects to characterize in homogeneous and precise ways exoplanet hosting stars in terms of astrophysical parameters, elemental abundances, and kinematical properties. Thanks to this kind of multidisciplinary approach, it is possible to put constrains on planet formation and evolutionary models. I will also show how the composition of exoplanet hosting stars can be correlated with the planetary properties making it able to trace the planetary migration scenario.

Star-planet interactions
Elemental abundances, Formation and evolution, Fundamental parameters, Kinematic properties

Hunting exoplanets around Ultracool Dwarfs with RV NIR-spectrographs

Poster751Roberto Varas; Instituto de Astrofísica de Andalucía

Poster AreaTue 08:30 - 17:50

The ultracool dwarfs are frequent in the solar neighborhood, but so far only three systems with exoplanets have been confirmed, TRAPPIST-1, LP 890-9 and Teegarden’s star. There are several reasons: (i) these stars are faint and the flux peaks in the near-infrared, but the RV information available in this part of the spectrum is lower than in the visible. Thus, we need more stable NIR spectrographs (CARMENES-PLUS) and larger telescopes (MARCOT). (ii) They are usually fast rotators (spectral lines get broadened). There is nothing to be done except to select the slowest ones. (iii) Planets around these stars are expected to be small, showing low RV amplitudes. The detectability expected for transits is around 2% whereas it increases to 55% with RV. The strategy used to find periodic signals in these stars is still a problem to be addressed, but we can find it by looking into the successful cases.

RV and transits
exoplanets, Ultracool Dwarfsnearinfraredspectrographs

Hyper-realistic simulations of observations of exoplanet atmospheres

Poster827Vincent Kofman; NASA Goddard Space Flight Center

Poster AreaTue 08:30 - 17:50

In order to realistically simulate the observations of exoplanet atmospheres, the 3D structure of the atmosphere needs to be considered. General circulation models can provide insights to behaviors such as winds, cloud/haze formation and distribution, and the abundances of molecules, which may all vary over time. Subsequently, one needs to consider the atmospheres’ interaction with stellar light, and constrain the photon fluxes originating from the planet, the star, and background fluxes. Finally, the noise originating from the astronomical and instrumental sources have to be calculated to constrain the relevance of the spectral features that are observed. Here, we use the Planetary Spectrum Generator to simulate observations of Solar System planets from a distance of 10 parsec, considering several current and future observatories.

Atmospheres
General circulations models

Imaging protoplanets from space: the HALPHA survey and beyond

Poster853Yifan Zhou; University of Virginia

Poster AreaTue 08:30 - 17:50

Direct-imaging detection of accreting planets marks a new era in planet formation research, allowing us to witness the process of planet assembly, understand mass accretion mechanisms, and explore the interactions between planets and their birth environment. We present a series of studies using HST imaging observations to search and characterize accreting planets. First, narrow-band H⍺ images obtained in the Hubble Accreting Luminous Protoplanets in H-Alpha (HALPHA) Survey have revealed a wealth of structures in the planet-forming disks, highlighting the sensitivity of the HST data and underscoring the complexity of distinguishing protoplanets from their formation environment. Second, results from multi-wavelength follow-up observations of protoplanet candidate AB Aur b indicate that the target’s optical and ultraviolet (UV) emission likely originates from scattered light, emphasizing the importance of UV observations for characterizing accreting planets. Finally, forthcoming time-resolved observations will constrain the variability of accreting planets and inform their accretion mechanisms.

Direct Imaging and Interferometry
direct imaging, gas giant planets, protoplanetary disks

Impacting Atmospheres: Linking Solid Accretion During Planet Formation to Exoplanet Composition

Poster610Emilia Vlahos; McGill University

Poster AreaTue 08:30 - 17:50

Spectroscopy data from Neptune-class exoplanets show that their atmospheric metallicities can range from 0.1 to 1000 times solar. The source of this diversity remains unknown. In this study, we aim to understand how variations in the formation conditions of these planets may lead to this wide range of post-accretion metallicities. To do this, we modelled the accretion of solids into the protoplanetary envelope during formation, solving numerically for the thermal evolution and vapourization of a single solid impactor. We report how the final atmospheric metallicity profile changes as a function of formation location, solid accretion rate, and the chemical species of the accreted material including silicates and icy pellets, thereby taking a first step towards linking the formation conditions with the observed atmospheric composition.

Atmospheres
Neptune Atmospheres, Planetesimal Accretion

Improving Low-mass Star Exoplanet Hosts' Masses and Radii Through the Combination of Gaia and TESS

Poster649Stephen Schmidt; Johns Hopkins University

Poster AreaTue 08:30 - 17:50

Precise and accurate host star masses and radii are critical for interpreting the transit observables of exoplanets that orbit low-mass stars. However, theoretical model radii for low-mass stars are inaccurate. In cases where a low-mass star transits a much brighter Sun-like star, the exoplanet-like light curve and single-lined spectroscopic binary solution of the system can be used to obtain a much more accurate mass and radius inference for the secondary. Here we present a method of using SB1 solutions presented in Gaia Data Release 3 in combination with TESS light curves to obtain low-mass star mass and radius inferences. We demonstrate this method by validating or confirming three TESS Objects of Interest: one is a transiting brown dwarf, and the other two are very low-mass stars. We thus verify that Gaia DR3’s single-lined spectroscopic binary solutions are valid down to the higher-mass brown dwarf semiamplitude regime.

RV and transits
Exoplanet Host Stars

Influences of data processing techniques on the interpretation of atmospheric spectra from JWST

Poster770Simon Schleich; University of Vienna

Poster AreaTue 08:30 - 17:50

The characterisation of exoplanet atmospheres through spectroscopic observations is the next step in advancing our understanding of exoplanetary systems. The field of exo-atmospheres is at a turning point thanks to the recent launch of the James Webb Space Telescope (JWST). However, the combination of increased sensitivity and wavelength coverage requires significant care in the reduction and interpretation of these observations, as the resulting data products determine the conclusions drawn by retrieval algorithms. We present an analysis of a JWST near-infrared observation of the Hot Jupiter WASP-39 b, comparing atmospheric characterisation results obtained from transmission spectra produced with varying data reduction assumptions. Investigating the impact of these assumptions on retrieved atmospheric parameters provides us with important insights into best practices for investigating the extensive amount of exo-atmosphere spectra expected from JWST.

Atmospheres
JWST

Inner Edges of Planetary Systems: Architectures and Stellar-Mass-Dependence

Poster775Mengfei Sun; School of Astronomy and Space Science, Nanjing University

Poster AreaTue 08:30 - 17:50

The position of the innermost planet in a planetary system could provide more potential information about planetary formation and evolution processes. Here we use the Kepler DR25 catalog to analyze and control the influence of stellar metallicity, stellar age, and observational bias to study the correlation between stellar mass and inner edge. A consistent conclusion was obtained under data sets: as the stellar mass increases, the position of the inner edge will also increase significantly. The correlation between stellar mass and the inner edge is about 0.765. When analyzing single-planetary systems and multi-planetary systems respectively, the correlations between them are about 0.696 and 0.803 respectively. Comparing the observed statistical results with the current model, it was found that the most consistent theoretical models are the PMS dust sublimation radius of a passive disk, an actively accreting disk with q = 1, and planet destruction by stellar tides.

Demographics & Architectures
exoplants, inner edges

Inspiration through space science: exoplanet themed education activities for secondary students

Poster698Kate Isaak; European Space Agency (ESTEC)

Poster AreaTue 08:30 - 17:50

The topic of exoplanets is connected directly to the very simple and profound question of whether we are alone in the Universe, capturing the imagination of scientists and the public alike. As such, it provides an excellent means through which to engage school students in some of the thrills of science and, critically, to teach science, technology, engineering and mathematics (STEM) core skills. In this contribution we give an overview of a collection of exoplanet inspired classroom activities and resources that have been developed through a collaboration between ESA Education and scientists working at ESA and beyond. The emphasis of the activities has been on transit photometry and more specifically ESA’s Cheops mission, with the underlying theme of using in-flight Cheops observations to engage young people. We combine the overview of the activities with an introduction to the ESA Education portfolio.

Other
educationinspirationactivities

Internal fractionation of atmosphere-forming volatile elements on low-mass exoplanets

Poster894Tim Lichtenberg; University of Groningen

Poster AreaTue 08:30 - 17:50

Low-mass exoplanets in a partially molten state open a novel window into key processes that shape the earliest, high-temperature evolutionary regimes of rocky worlds and their long-lived climate states. In this talk I will outline how magma ocean dynamics and core-mantle segregation influence the coupled interactions between largely molten interiors and volatile envelopes. The physical and chemical coupling between magma layers and their outgassing atmospheres can fractionate the dominant volatiles observable in the atmosphere to a degree that is testable with current instrumentation. As a key example, nitrogen species can be suppressed in the atmosphere if the volatile envelope is in direct contact with a chemically reduced molten interior. Using the high-priority targets K2-18 b, 55 Cnc e, GJ 367 b, and TOI-561 b, I will outline how we can test key principles of planetary interiors and atmospheric formation relevant to low-mass and potentially habitable exoplanets on wider orbits.

Interiors
atmosphere formation, interior evolution, lowmass exoplanets

Investigating Star-Planet Compositional Ties for Systems with Iron-Poor Host Stars

Poster598Daisy Turner; University of Birmingham

Poster AreaTue 08:30 - 17:50

As stars and planets are formed in the same environment, a fundamental interconnection should exist between the compositions of planets and their host stars. Exploring this relationship offers profound insights into the intricate history of their formation and evolution. Unravelling such complexities necessitates a diverse stellar sample that spans a wide range of chemical balances such as [α/Fe]. Optimal targets for this inquiry are planetary systems orbiting iron-poor, alpha-enhanced host stars, as they present an opportunity to study the composition of planets orbiting stars with chemical compositions vastly distinct from the Sun. In this poster, I present preliminary results that illustrate my current efforts to expand this sample, focusing on small planets orbiting such unique stellar hosts.

Star-planet interactions
ironpoor stars, small planets, stellar abundances

Investigating the climate of WASP-18 b in 3D

Poster639Lennart Van Sluijs; University of Michigan

Poster AreaTue 08:30 - 17:50

Ultra hot Jupiters (UHJs) are unique extrasolar laboratories excellent for studying extreme atmospheric physics. Their inherent 3D nature results in spatial variations of their temperature, chemistry, and winds. Although challenging, these features are observable as they orbit their star with high-resolution cross-correlation spectroscopy (HRCCS). In the benchmark UHJ WASP-18 b, evidence in the form of molecule-dependent velocity offsets has been inferred using a 1D model in Brogi et al. (2023) but inherent to the 1D approach is that it did not address these spatial variations. I will present novel realistic simulated observations using a 3D GCM, which includes magnetic drag, to investigate the cause of these observed molecule-dependent velocity offsets. Based on these results, I will discuss important implications when characterizing a 3D exoplanet using a simplified 1D HRCCS retrieval.

Atmospheres
Global Circulation Model, NIR observations

Is there Glory in the atmosphere of WASP-76 b ?

Poster875Vikash Singh; INAF, Osservatorio Astrofisico di Catania; Ludmila Carone; Space Research Institute, Austrian Academy of Sciences

Poster AreaTue 08:30 - 17:50

Since the detection in high-resolution transit spectroscopy of a signature indicating an asymmetry between its two limbs by Ehrenreich+2020, WASP-76 b has been one of the most studied exoplanets. While it has been confirmed by several studies (Kesseli+2021, Pelletier+2023), the origin of this asymmetric signature is still debated (e.g. Savel+2022, Wardenier+2021).We present a holistic analysis of all eclipse and phase-curve observations available including, but not limited to, 37 new phase curves (3 from CHEOPS, 34 from TESS) and 20 additional occultations (from CHEOPS). Interestingly, we unearthed an asymmetric signature in the visible phase-curves. The CHEOPS phase-curves feature a sharp increase in the flux emanating from the Eastern hemisphere. We hypothesize that it could originate from a strong and anisotropic reflection produced by spherical droplets above clouds called Glory effect. This would reinforce the idea that condensation occurs at the Eastern terminator as proposed by Ehrenreich+2020. Based on Demangeon+2023 submitted.

Atmospheres
Cloud, Hazes and Condensation, Phase curve, Reflected light

JWST Coronagraphic observations of exoplanets in the mid-infrared with MIRI: results and assessment.

Poster1653Clément Perrot; LESIA, Observatoire de Paris

Poster AreaTue 08:30 - 17:50

Two years after the first coronagraphic images of an exoplanet in mid-infrared with the JWST, dozens of them have been imaged, or attempted to be imaged, as part of a dozen programs with MIRI coronagraphs.

In this poster we will present the characterization of exoplanets observed with the ExoMIRI GTO (HR 8799 bcde, HD 95086 b, GJ504 b and HD 106906 b) and the hunt of sculptor exoplanets inside debris disks, between 10 and 23µm.

We will also present our methods for characterizing exoplanets in complex systems with bright inner disks and background objects.

Finally, we will discuss the observational and calibration strategies and their impact on the exoplanet characterization for future programs. In particular, the impact of dedicated background and reference star observations.

JWST Results
CoronagraphyMIRImidinfrared

K-Stacker's multi-epoch recombination, and enhanced contrast capabilities for the E-ELT.

Poster760Hervé Le Coroller; LAM

Poster AreaTue 08:30 - 17:50

This presentation will explore the unique K-Stacker ability to recombine high contrast imaging observations from multiple epochs. This approach significantly enhances the detection limit of direct imaging techniques. I will highlight a practical application of K-Stacker, allowing to probe planets smaller than 1.5 Jupiter radius in the eps Eri area (< 4 au), using the SPHERE ZIMPOL instrument. Additionally, the presentation will showcase the potential of K-Stacker in the context of future astronomical instruments like HARMONI on the E-ELT. Through simulated images, we demonstrate how K-Stacker can exploit the full capabilities of these instrument, pushing the boundaries of our exoplanet detection limits and reveling the orbital parameters of the detected planets. We will demonstrate that K-Stacker is more than just an algorithm; it represents a novel observational strategy in high-contrast imaging that minimizes telescope time while achieving the highest contrasts and extracting unbiased orbital parameters.

Direct Imaging and Interferometry
coronagraph, EELT, exoplanets

K2-22b: A Rocky World Inside Out

Poster826Nick Tusay; Penn State University

Poster AreaTue 08:30 - 17:50

The disintegrating ultra-short period exoplanet K2-22b offers an opportunity to probe the interior composition of a rocky exoplanet around a main sequence star for the first time, via the transmission spectrum of the evaporating dust obtained with MIRI LRS slitless spectroscopy on JWST. By comparing the transit transmission spectra to detailed extinction and scattering models, this program aims to determine the mineralogical make-up of the dust outflowing from K2-22b, and therefore the composition of the planet's interior. The relative mineralogical abundances in the dust will provide insight into whether it is crustal, mantle or core material that is evaporating. Assuming mantle material is evaporating, these observations will determine the Mg/Si and Fe/Si ratios of the planet -- which drives important questions of interior dynamics and habitability. These observations will be complimented with simultaneous optical data that will enable the breaking of degeneracies in the mineralogical models.

JWST Results
Disintegrating Planet, Interiors, Rocky Worlds

Kepler and Beyond: An Updated View of Earth-sized Planets in the Habitable Zone

Poster789Galen Bergsten; Lunar and Planetary Laboratory, The University of Arizona

Poster AreaTue 08:30 - 17:50

The frequency of Earth-sized planets in the habitable zone (η⊕) is a key parameter in the design and success of future missions like the Habitable Worlds Observatory. In the past decade, the Kepler sample has been used to study η⊕ for both M and FGK stars. However, most studies have not included recent advancements – like new vetting statistics and Gaia-informed parameter revisions – which have reshaped our understanding of Kepler’s planets and stars. We conducted an updated investigation into η⊕ around Kepler’s M dwarfs, and compared our findings with similarly comprehensive estimates from Sun-like stars. We find that, unlike previously believed, the Kepler sample does not offer evidence supporting an increase in η⊕ from FGK to M stars. We will discuss efforts to improve our understanding of η⊕ by supplementing the Kepler sample with additional surveys, and exploring the impact of other planets in or near the habitable zone.

Demographics & Architectures
Earthsized Planets, eta_Earth

Leveraging a 3D Global-Climate-Model for climate studies of hot giant gaseous exoplanets and brown dwarfs

Poster934Lucas Teinturier; Lesia, Observatoire De Paris

Poster AreaTue 08:30 - 17:50

Key parameters controlling planetary climates are the irradiation, the intrinsic heat flux and the rotation rate. Observations of giant (exo-)planets and brown dwarfs allow us to explore a large parameter-space and to reveal the diversity of climate regimes.We will discuss the latest development of the generic-Planetary-Climate-Model for the atmospheric study of hot giant gaseous objects.First, we will discuss the case of a tidally-locked Hot Jupiter, WASP-43b, and explore the dynamical, thermal and cloud structure of such objects. We show that clouds are mandatory to explain the HST-Spitzer-MIRI phase-curves.Secondly, we will discuss the impact of eccentricity and clouds on the thermal-dynamical structure of Hot Jupiters, as ~ 20% of Hot Jupiters display non-circular orbits. FInally, we will present our simulations of field brown dwarfs around the L/T transition, especially focusing on the cloud distribution as a function of effective temperature and discuss the observational consequences for such objects.

Atmospheres
numerical simulations

Making a MESS out of TESS: Searching for microlensing by free-floating planets with TESS

Poster791William DeRocco; University of California, Santa Cruz

Poster AreaTue 08:30 - 17:50

During the chaotic early stages of system formation, gravitational scattering is expected to efficiently eject a large number of rocky bodies over a wide range of masses. In the terrestrial-mass range, these ejecta constitute "free-floating planets" (FFPs) and are expected to outnumber their bound counterparts. Despite the large abundance, FFPs are a difficult target for observation. The only existing observational technique sensitive to these objects is gravitational microlensing. Though TESS is primarily sensitive to transits, its high sensitivity and rapid cadence provide an opportunity to search for microlensing events as well. In this talk, I will describe the status of an ongoing search in archival observations, which is expected to yield as many as ten detectable FFP events in the terrestrial range. If detected, these events will considerably increase our knowledge of the demographics of this population, with implications for models of planetary formation and dynamics.

Microlensing and Astrometry
TESS

Mapping Exoplanet Atmospheres with Direct Ground-based Observations

Poster795Ben Sutlieff; University of Edinburgh

Poster AreaTue 08:30 - 17:50

Atmospheric features, such as giant storms, cause variability in exoplanet atmospheres as they rotate in and out of view. By monitoring this variability, we can map their physical appearance. Ground-based observatories reach the high contrasts and resolution needed to monitor these faint companions, but a lack of reference stars makes this difficult. I present a new approach from our differential spectrophotometric monitoring campaign of a substellar companion using NALES/LBT, an integral field spectrograph combined with a vAPP coronagraph. Unlike focal-plane coronagraphs, the vAPP reaches deep contrasts while simultaneously providing an unsaturated stellar reference PSF for removing variations due to Earth’s atmosphere. We create light curves of the companion directly to search for atmospheric inhomogeneities. I will show the ~4-5% differential precision achieved with just one night of monitoring and our analysis of astrophysical features in the light curve. This method enables high-precision monitoring for directly-imaged exoplanets inaccessible to space-based telescopes.

Direct Imaging and Interferometry
Brown dwarfs, Exoplanet atmospheres, High angular resolution

Measuring Rotation and Wind Velocities on Exoplanets through Occultations Observed at High Spectral Resolution

Poster788Vincent Yariv; IPAG

Poster AreaTue 08:30 - 17:50

Hot Jupiters are expected to rotate synchronously, and general circulation models predict strong eastward winds, redistributing the heat from their permanent daysides to their nightsides. While photometric and low-resolution spectroscopic measurements have been used to corroborate such models, direct measurements of rotation/wind velocities using Doppler-resolved spectroscopy remain a challenge. One reason for this is the poor sensitivity to line broadening of the cross-correlation methods used to recover the planetary signal at high spectral resolution. Secondary eclipses could be used to improve constraints on exoplanetary rotation/wind speeds, by leveraging instead a line-shifting effect analogous to the Rossiter-McLaughlin effect observed on stars. Using simulations and signal injection on real data, we explore the potential of this novel method today and in the ELT era.

Atmospheres
Hot Jupiters, Occultation, Rotation

Measuring tracers of planet formation in the atmosphere of WASP-77Ab

Poster912Billy Edwards; SRON, Netherlands Institute of Space Research

Poster AreaTue 08:30 - 17:50

Elemental ratios have long been proposed as potential tracers of planetary formation. I will present a comprehensive atmospheric retrieval study of the hot-Jupiter WASP-77Ab using eclipse observations from HST and JWST. From these data, three molecules are identified: H2O, CO and TiO. Using the abundances of these species, the C/O ratio is determined to be consistent with that of the planet’s host star. However, the results suggest that the general enrichment of the atmosphere (i.e., metallicity) is sub-stellar, depleted in C and O, but Ti appears to be slightly super-stellar. I will discuss the potential formation pathways that could explain these results. Additionally, I will present the differences found between the results of this work and previous studies. Particular focus will be placed upon how different datasets, and different analyses of the same dataset, can lead to disparate results and how these can impact the inferences about the formation history.

JWST Results
Elemental Ratios

Measuring XUV irradiation and modelling the atmospheric escape and evolution it drives

Poster619George King; University of Michigan

Poster AreaTue 08:30 - 17:50

We present results from our ongoing work to characterise exoplanetary systems at high-energy, and model the resulting effects of this emission on planetary atmospheres. In particular, we focus on planets in and around populations features such as the Neptunian desert and the radius valley. With X-ray observations from a slew of telescopes such as XMM and Chandra, we measure the irradiation level at the planets and estimate the current level of mass loss ongoing. The measurements also act as key anchor points for the lifetime stellar XUV in our modelling of the evolutionary history and future of the planets using MESA. We are using the results from those simulations to verify the planets’ compatibility with the theorised sculpting of population features by XUV-driven escape.

Formation and evolution
XUV irradiation

Metal-rich stars are less friendly to life: The UV paradox

Poster937Anna Shapiro; Max Planck Institute for Solar System Research (MPS)

Poster AreaTue 08:30 - 17:50

Ozone is one of the most important atmospheric constituents for sustaining life on Earth. Atmospheric ozone protects the biosphere against harmful UV radiation by absorbing it. Here, we address the question how the thickness of the ozone layer would differ if the Earth were hosted by another solar-like star instead of the Sun. Namely, we model the atmospheres of ExoEarths orbiting solar-like stars with different values of metallicity and effective temperature. We found that although metal-rich stars emit less UV radiation than metal-poor stars, the drop in ozone concentration leads to higher surface UV on their planets. This means that the Universe gets less life friendly as it ages because stars become more metal-rich. We also study the response of the ozone layer and surface UV to different disturbing factors such as increase in stellar magnetic activity, supernova explosion and volcanic eruptions.

Atmospheres
Earthlike atmosphere, habitability, metallicity

Midnight Molecules: Photodissociations and Transport-Induced Chemistry on Hot Exoplanets

Poster793Robin Baeyens; University of Amsterdam

Poster AreaTue 08:30 - 17:50

The day and night sides of hot giant exoplanets are widely contrasting environments with temperature differences up to 1000 K. Yet, atmospheric circulation leads to an exchange of heat and chemical species between both hemispheres. As observational techniques mature, it has now become possible to probe these chemical gradients and investigate chemical transport, condensation, cold trapping, and ionization in great detail.

We present photochemical model results of hot exoplanetary atmospheres and show that photodissociation can have a global impact. Stellar photons can even break down triple-bonded CO and N2 molecules on the day side. The resulting radicals are subsequently transported to the night side, where they kick-start new chemical pathways. Such mechanism could explain the enigmatic observation of HCN on WASP-76 b. Finally, we broach the subject of ionization in exoplanet atmospheres and propose avenues to tackle neutral-ion chemistry in the future.

Atmospheres
atmospheric circulation, chemical composition, photochemistry

Modeling Heterogeneities of Habitable Exoplanets in Polarized Reflected Light

Poster547Kenneth Goodis Gordon; University of Central Florida

Poster AreaTue 08:30 - 17:50

Habitable exoplanets are expected to contain atmospheric and surface heterogeneities similar to Earth, with the diurnal rotation, seasonal changes, and weather patterns of the planets resulting in complex, time-dependent signatures. Due to its sensitivity to the micro- and macro-physical properties of a planet’s atmosphere and surface, polarimetry provides an important tool that, in tandem with traditional flux-only observations, will enhance the characterizations of these worlds. Here we present the results of our theoretical study investigating the visible to near-infrared linear spectropolarimetric signatures of different heterogeneous terrestrial exoplanet archetypes. The contributions from the different surfaces, clouds, hazes, and atmospheres result in asymmetric phase curves and variable spectra that allow us to begin to resolve degeneracies between habitable and non-habitable scenarios. Our models provide important predictions of expected polarized and unpolarized signatures of terrestrial exoplanets that will help guide the designs of future polarimeters to carry out observations of these worlds.

Habitability
Habitable planets, Spectropolarimetry

Multi-physics interaction between planetary atmospheres and their host stars.

Poster757Alexandre Gillet; CEA

Poster AreaTue 08:30 - 17:50

Planetary mass-loss is governed by several physical mechanisms. For close-in planets, it is believed that thermal hydrodynamic and photochemical escape dominate. Nevertheless, the important effect of secondary ionisation and the associated reduced heating of upper atmospheres has been overlooked in the past, and could play a dominant role in setting the mass loss rate of close-in planets as well as determining the observational signatures (e.g.Lyα) of the escape. We perform HD and MHD simulations with the PLUTO code of an atomic hydrogen planetary atmosphere. We present our results and analysis of the quantitative effect of secondary ionisation by photoelectrons, of geometrical effects between 1D and 2D, of the impact of the shape of different XUV stellar spectra, of flares on the planetary atmosphere, and the effect of a planetary magnetosphere. With these results, we provide a coherent and quantitative assessment of the dominant processes of atmospheric escape of close-in exoplanets.

Star-planet interactions
Escape processes, Mass loss, Secondary ionisationMHD simulations

NIRISS vs WFC3 – Exoplanet Showdown : A Comparative Analysis of Transmission Spectra

Poster932Chloe Fisher; University of Oxford

Poster AreaTue 08:30 - 17:50

With the dawn of the JWST era comes an explosion in the resolution and wavelength coverage of transmission spectra of exoplanets from space-based instruments. This brings an expected increase in the information content of these spectra, when compared with previous data from the Hubble Space Telescope. However, the degree and nature of this increase is not obvious. In this work, we attempt to quantify the information gain when comparing spectra from HST’s WFC3 instrument with its most similar JWST counterpart – NIRISS. We perform retrievals on WFC3 and NIRISS spectra of the hot Jupiter WASP-39b, and determine whether the improved constraints on atmospheric parameters are due to the increase in wavelength coverage or resolution/precision. We also combined these with the STIS spectra and discuss inconsistencies in the data, along with issues that can arise from joint retrievals.

Atmospheres
HST, JWST, Retrievals

Non-LTE hydrodynamic XUV-evaporation of exoplanet secondary atmospheres

Poster642Richard Chatterjee; University of Oxford

Poster AreaTue 08:30 - 17:50

JWST detected light emitted from a cool (~500K) rocky exoplanet for the first time, revealing the Earth-sized TRAPPIST-1b as likely being airless. Even the rocky planets orbiting in the habitable zone of such an M-dwarf star are exposed to intense XUV fluxes, so are excellent probes for understanding the loss and survival of secondary atmospheres, such as those dominated by nitrogen or carbon-dioxide.

We present a new framework of analytic models exploring the XUV-induced transonic radial outflow of high-molecular-weight upper atmospheres in a state of collisional-radiative non-LTE. By breaking down N2 or CO2 molecules, XUV photons can generate steep thermospheric inversions able to connect a temperate surface to the hot atomic upper-atmosphere conditions necessary for substantial escape. However, high-temperature collisions excite atoms, triggering spontaneous emission that acts as a cooling thermostat, limiting escape. Our work outlines how this non-linear physics of hydrodynamic escape shapes secondary atmospheres in varying star-planet conditions.

Atmospheres
atomic line cooling, cosmic shoreline, hydrodynamic onset, nitrogen escape

Observability of substructures in planet-forming disk in (sub)cm wavelength with SKA and ngVLA

Poster574Yinhao Wu; University of Leicester

Poster AreaTue 08:30 - 17:50

Current imaging observations of protoplanetary disks using ALMA primarily focus on the sub-millimeter wavelength, leaving a gap in effective observational approaches for centimeter-sized dust, which is crucial to the issue of planet formation. We investigate the potential of SKA1-Mid, ngVLA, and SKA2 for imaging protoplanetary disks at sub-cm/cm wavelengths. We discover that both SKA and ngVLA will serve as excellent supplements to the existing observational range of ALMA, and their high resolution enables them to image substructures in the disk's inner region. Our results indicate that SKA and ngVLA can be utilized for more extended monitoring programs in the centimeter waveband. While in the sub-centimeter range, ngVLA possesses the capability to produce high-fidelity images within shorter observation times than previous research, holding potential for future survey observations. We also discuss for the first time the potential of SKA2 for observing protoplanetary disks at a 0.7 cm wavelength.

Future missions/instrumentation
Hydrodynamics, simobserve

On the Planet-Forming Environment of the Milky Way's Thick Disk

Poster546Tim Hallatt; McGill University

Poster AreaTue 08:30 - 17:50

Close-in ($lesssim$1 AU) super-Earths and sub-Neptunes are found to be ${sim}50{%}$ less common around stars in the Milky Way's thick disk as compared to those in the thin disk. One key difference between the two stellar populations is the time at which they emerged: thick disk stars are the likely product of cosmic noon (redshift $z sim 2$), an era characterized by high star formation rate, massive and dense molecular clouds, and strong supersonic turbulence. We demonstrate that the nebular conditions around thick disk stars were subject to extreme UV radiation and bolometric heating, shortening the dispersal time of protoplanetary disks to $sim$0.5 Myr, severely limiting the timescale over which planets can assemble. Our calculations predict that the deficit in the planet occurrence rate around thick disk stars should be even more pronounced at wide orbital separations and particularly for gas-rich planets.

Formation and evolution
protoplanetary disksphotoevaporation

On-Sky performances and science objectives of the new nIR spectrograph NIRPS

Poster871François Bouchy; Geneva Observatory

Poster AreaTue 08:30 - 17:50

The Near-InfraRed Planet Searcher (NIRPS) is a new ultra-stable near-infrared (YJH) spectrograph equipped with an AO system, installed on ESO 3.6-m Telescope in La Silla, Chile and operated together with the exoplanet hunter HARPS. Achieving a radial velocity precision close to 1 m/s, NIRPS is designed to explore the exciting prospects offered by the M dwarfs, focusing on three main science cases: 1) High-precision RV survey of M dwarf aiming at detecting Earth-like planets in the habitable zone; 2) Mass (and density) measurements of planetary candidates orbiting M dwarfs from transit surveys, and 3) Atmospheric characterization of exoplanets via transmission spectroscopy. NIRPS consortium started in April 2023 a comprehensive program totalizing 725 nights over 5 years. We present the technical aspects of this new instrument, its main science objectives, the observing strategy and the first results of NIRPS survey after 1 year of operation.

Future missions/instrumentation
nIR spectrograph

PEGASUS: PHOENIX EUV Grid And Stellar UV Spectra

Poster707Sarah Peacock; University of Maryland Baltimore County

Poster AreaTue 08:30 - 17:50

With the continually increasing number of newly discovered exoplanets, the quest to characterize the high energy radiation environment of each individual system becomes a larger and more arduous task. Stellar EUV flux contributes to atmospheric escape and water loss on close-in planets, therefore having a reliable catalog of EUV spectra for all host stars will be a valuable resource to better understand and interpret the atmospheres of exoplanets. To simplify the endeavor of computing spectra for each host star, we present a grid of 1,500 generalized EUV spectra for M and K stars between 2500 – 5000 K. These spectra are computed from PHOENIX upper atmosphere models and GALEX FUV+NUV fluxes are used to identify the appropriate EUV spectrum. Our webtool is searchable by target name or user-inputted parameters and also includes an option to download full UV spectra for generic M and K stars of each subtype.

Star-planet interactions
Low mass stars, Ultraviolet

Phase shifts between RVs and stellar variability indicators

Poster808Annelies Mortier; University of Birmingham

Poster AreaTue 08:30 - 17:50

Detailed characterisation of small exoplanets is currently hindered by radial velocity signals arising from the star's intrinsic variability. In extracting the precise radial velocities, we can also extract spectral line profile information. These are useful indicators for the stellar variability processes and often crucial in modeling the Keplerian planet signals. However, for them to be optimally used in a global model, it is essential to bear in mind that these indicators are not directly correlated with the radial velocities, but rather shifted by several days. In this poster I will give an overview of this effect as studied on Solar data from the HARPS-N spectrograph, which has been continuously gathering data since 2015.

RV and transits
Activity Indicators, HARPSN

Planet migration in windy disk

Poster575Yinhao Wu; University of Leicester

Poster AreaTue 08:30 - 17:50

Our study investigates how wind-driven accretion impacts planetary migration, a key link between planet formation models and observed exoplanet statistics. Utilizing the FARGO3D code, we conducted two-dimensional hydrodynamical simulations of planet-disk interactions on the (r, φ) plane, quantitatively exploring the relationship between planet-to-stellar mass ratio and wind strength, which influences planetary migration behaviors. Our findings provide a qualitative analysis and theoretical explanation of this phenomenon. The study underscores the importance of including wind-driven accretion in long-term protoplanetary disk evolution models, as it significantly affects migration rates and directions of planets formed within these disks.

Formation and evolution
MHD disk wind, planet migration, planetdisk interaction

Planetary Perturbers - searching for flaring star-planet interaction with Kepler and TESS

Poster562Ekaterina Ilin; Netherlands Institute for Radio Astronomy (ASTRON)

Poster AreaTue 08:30 - 17:50

When a planet orbits its host star in a very close orbit, it can become an in-situ probe of the stellar magnetosphere. As the planet ploughs through the magnetized plasma surrounding the star, it can perturb the field, and trigger flares in the stellar corona.

We investigated the correlation between flares and the planet's orbital period using time series photometry from Kepler and the Transiting Exoplanet Survey Satellite. Out of 1811 star-planet systems, 25 planet hosts showed three or more flares. For these 25, we derived the energy dissipated into the stellar magnetosphere through planetary perturbation.

The systems fall into two categories: an inactive branch without flare clustering, and a potentially active one where clustering intensifies with increasing power of interaction. Notably, HIP 67522 displayed the strongest flare clustering (p < 0.006). We have now begun to closely monitor the 17 Myr old Hot Jupiter host with the CHEOPS satellite.

Star-planet interactions
flares, Kepler, magnetic starplanet interaction, TESS

Predicting and Finding Temperate Terrestrial Planets and Optimizing Their Future EPRV Observations

Poster823Jeremy Dietrich; Arizona State University

Poster AreaTue 08:30 - 17:50

We’re likely missing ≳90% of the planets in the Solar Neighborhood, and some of those hidden planets are temperate terrestrial planets with a potential to host extraterrestrial life. But how can we efficiently locate these planets? Could they be hiding in already known systems? I investigated the orbital architectures and planetary characteristics of all nearby exoplanet systems and determined which are most likely to host a temperate terrestrial planet. High-precision radial velocity observations have begun monitoring the 10 strongest candidate systems. Using the DYNAMITE software package, I analyzed exoplanetary systems by combining the specific but incomplete observational data with population-level statistical models and constraints on system stability, and then predicted the presence and parameters of additional unseen planets. The RVs will provide prioritized targets for EPRV characterization and the future NASA flagship mission searching for biosignatures, potentially bringing us significantly closer to finding life elsewhere in the universe.

Demographics & Architectures
Architectures, RV

Prediction and search for free-floating planets

Poster752Qiyue Qian; Tsinghua University

Poster AreaTue 08:30 - 17:50

Free-floating planets (FFPs) are expected to be common in our Galaxy. The mass function and number density of the FFP population can provide constraints to the planet formation theories. Microlensing is currently the only method that can detect FFPs in a wide mass and distance range. We use quasi-image level simulation to predict the FFP event rate of the Korean Microlensing Telescope Network (KMTNet) survey, which differs from the current discovered FFP number. To further understand the difference, we are systematically searching for FFPs in KMTNet historical data, which may re-discover missing FFPs, and I will introduce the recent progress.

Microlensing and Astrometry

Probing gas giant atmospheres using sulfur chemistry

Poster613Rens Waters; Radboud University

Poster AreaTue 08:30 - 17:50

The spectroscopic capabilities and sensitivity of the James Webb Space Telescope (JWST) have recently given access to new molecular species, by means of transit spectroscopy. In particular the detection of the sulfur bearing species SO2 (Tsai et al., Dyrek et al.) has gained considerable interest, because this gives insight in the formation history of planets and is a signpost of photochemistry. Planets that have accreted planetesimals or dust are expected to show a high atmospheric abundance of ‘metals’, including oxygen and sulfur. The formation of SO2 is a photochemical process. Therefore, both photochemistry and formation history determine the possible presence and abundance of SO2. We present a JWST Cycle II program aimed at disentangling the effect of photochemistry and formation history on the presence and abundance of SO2 in the atmospheres of three H/He dominated hot Neptune-Jupiter mass planets whose parent stars have substantially different temperatures and radiation fields.

Atmospheres
hot gas giant atmospheres, photochemistry, transit spectroscopy

Probing super-Jupiter formation: Unraveling the mechanisms through a homogeneous atmospheric analysis.

Poster921Paulina Palma Bifani; Laboratoire Lagrange

Poster AreaTue 08:30 - 17:50

Super Jupiter formation mechanisms, including core accretion and gravitational instabilities in protoplanetary disks, and stellar-like mechanisms in molecular clouds, remain subjects of exploration. Over a decade, the carbon-to-oxygen ratio emerged as a crucial parameter that provided information about the location of the gas and solids accretion. Our study examines a homogenous sample of 24 low-mass (mass < 30 Jupiter masses) companions and isolated objects through medium-resolution K-band spectra (resolution ~5000) obtained with SINFONI at the VLT. We uniformly measured their carbon-to-oxygen ratios and metallicities using ForMoSA, a Bayesian forward modeling Python package. We conducted preliminary statistical assessments to analyze these values in connection with the age, mass, temperature, gravity, and semi-major axis of each target. This comprehensive approach, linked to simulations, probes the boundaries of planetary-mass formation mechanisms, offering valuable insights into their operational limits.

Atmospheres
C/O ratioPhysical properties, Formation and evolution, Spectral library

Reassessing Water Worlds: Machine Learning Analysis of Small Planets around M-type Stars

Poster868Silke Dainese; Aarhus University, Department of Physics and Astronomy

Poster AreaTue 08:30 - 17:50

Water worlds, theoretical planets almost entirely veiled in water, have sparked discussions in recent literature. Through the lens of machine learning and a focused analysis of an up-to-date sample of small planets orbiting M-type stars, this work searches for evidence of water worlds within the mass-radius-density distribution of planets.

This work's findings do not support the water world paradigm. The current 2023 sample of small planets can be categorized into two groups: distinct terrestrial planets, primarily composed of rocky material, and sub-Neptunes, surrounded by primordial H/He atmospheres of various thicknesses.

Demographics & Architectures
Machine Learning, Planetary Diversity

Refining the planetary mass-metallicity relation for giant planets

Poster593Solène Ulmer-Moll; Space Research and Planetary Sciences, Physics Institute, University of Bern

Poster AreaTue 08:30 - 17:50

Warm giant planets provide a unique opportunity to better understand the formation and evolution of planetary systems. Their atmospheric properties remain largely unaltered by the impact of the host star or by inflation mechanisms. Thanks to several years of photometric and radial velocity campaigns, the sample of warm giant planets is steadily increasing, bridging the gap between the well-known hot Jupiters and the Solar System giants. Combining precise masses, radii, and ages with a state-of-the-art planetary evolution model, we estimate the interior composition of warm gas giants. In this talk, I present the impact of several modeling assumptions (e.g. H/He equation of state, core mass). Performing Bayesian inference on a new grid of evolution curves, I measure the metal enrichment of the whole sample of warm giant planets homogeneously. I refine the planetary mass-metallicity relation (a predicted outcome of core-accretion models) and test its dependence on orbital and stellar parameters.

Interiors
Gas giants, Interior modeling

Revealing the chemistry of DoAr33: a system with an intermediate C/O ratio

Poster710Maria Jose Colmenares Diaz; University of Michigan

Poster AreaTue 08:30 - 17:50

The C/O ratio has been suggested as a method to link the composition of explicit locations within protoplanetary disks with a potential fingerprint that connects to the atmospheric composition of gas giants. Recent JWST and ALMA measurements reveal a potential diversity in inner and outer disk compositions. Tabone et al. (2023) observe a hydrocarbon-rich, low water vapor system consistent with an elevated C/O ratio (>1). In contrast, Gasman et al. (2023) find a solar C/O ratio where ALMA detects elevated ratios in the outer disk (>5 au). We focus on the JWST spectra of DoAr 33, obtained as part of the JDISCS program. The spectrum shows evidence of an intermediate state in the chemistry, a rich hydrocarbon chemistry is observed alongside water vapor. We present models that attempt to reveal the C/O ratio of this disk and elucidate the key facets in the chemistry that may drive inner disk composition.

JWST Results
protoplanetary disks

Robustness of the CO2-H2O-O3 Triple Signature as an Exoplanetary Biomarker

Poster928Benjamin Taysum; Deutsches Zentrum für Luft-und Raumfahrt (DLR)

Poster AreaTue 08:30 - 17:50

The simultaneous detection of ozone (O3), water (H2O), and carbon dioxide (CO2) within a rocky planet atmosphere is considered an indicator of the biological production of oxygen (O2) at the surface. We model the atmospheric composition of Earth-mass planets with and without oceans and active biospheres for a range of background CO2abundances across the habitable zone of a Sun-like star. The potential of biologically inactive planets for producing this “triple signature” through means of atmospheric chemistry, and the risks posed for False-Positive inferences of life, are studied. Identifiers of False-Positive cases that may be observable by future missions such as ESA’s LIFE and NASA’s HWO will be crucial to accurately infer the presence of extraterrestrial biospheres on habitable zone planets.

Atmospheres
Rocky exoplanets

Rocky planet formation in compact disks around M dwarfs

Poster1652Mariana Sanchez; Leiden Observatory

Poster AreaTue 08:30 - 17:50

Due to the improvements in radial velocity and transit techniques, we know that rocky planets, in particular close-in super-Earths, in compact configurations are the most common ones around M dwarfs. On the other hand, thanks to the high angular resolution of ALMA we know that most disks around very low mass stars are rather compact and small, which favours the idea of an efficient radial drift that could enhanced planet formation in the terrestrial zone. Motivated by these results, we have investigated rocky planet formation around M dwarfs driven by pebble accretion through N-body simulations. We assumed that planet formation took place in compact dust disks caused by efficient dust radial drift. In the simulations we incorporated planet-disk interactions and tidal and relativistic corrections that include the evolution of the luminosity, radius and rotational period of the star. For our standard model we used different gas-disk viscosities and initial embryo distributions. For different stellar masses we also studied planet formation by planetesimal accretion. Our main result is that the sample of simulated planets that grow by pebble accretion in a gas-disk with low viscosity can reproduce the low-mass exoplanet population around M dwarfs in terms of multiplicity, masses and semi-major axis. Furthermore, we found that a gas disk with high viscosity can not reproduce the observed planet masses. Also, we show that planetesimal accretion favours the formation of water worlds and small planets that so far have not been detected. This work points towards a new approach for the disk conditions needed to study rocky planet formation around M dwarfs.

Demographics & Architectures
Demographics & Architectures, Formation and evolution

Rocky Planet or Water World? The Observability of Low-Density Lava World Atmospheres

Poster829Anjali Piette; Carnegie Earth & Planets Laboratory

Poster AreaTue 08:30 - 17:50

An emerging population of low-density super-Earths may be explained by volatile-rich interiors. Among these, low-density lava worlds have dayside temperatures high enough to evaporate their surfaces, providing a unique opportunity to probe their interior compositions and test for the presence of volatiles. Using self-consistent 1D atmosphere-interior models, we explore the atmospheric observability of low-density lava worlds, focusing on three case studies with sub-stellar temperatures spanning ~1900-2800 K: HD86226c, HD3167b and 55Cnce. Given the possibility of mixed volatile and silicate interior compositions for these planets, we consider a range of mixed volatile and rock vapor atmospheric compositions. We find that H2O and/or CO2 could be detected with as few as ~5 JWST secondary eclipses. Several observations of low-density lava worlds in JWST Cycles 1 and 2 will therefore be sensitive to the presence of volatiles in their atmospheres, testing the presence of volatile-rich interiors among the super-Earth population.

Atmospheres
Atmosphereinterior interactions, Lava worlds

Rossiter-McLaughlin observations with FEROS

Poster782Melissa Janice Hobson; Observatoire de Genève

Poster AreaTue 08:30 - 17:50

FEROS is a fibre-fed high-resolution (R=50000) spectrograph at the MPG 2.2 telescope at La Silla, reaching an RV precision of a few m/s on bright stars. Many hot and warm Jupiter exoplanets such as those being unveiled by TESS have Rossiter-McLaughlin (RM) amplitudes of 20m/s or higher, a regime for which FEROS is perfectly suited. However, it has never before been used to measure the RM effect on a transiting planet. In this contribution, we present the first RM measurements obtained with FEROS, validating the performance on the hot Jupiter WASP-18 b, which has an RM amplitude of 100 m/s and is variously reported in the literature as aligned or marginally misaligned. Weather permitting, we will also present a first measurement of the spin-orbit alignment of TOI-150 b, a warm Jupiter with a predicted RM amplitude of 50m/s, whose obliquity is not yet known.

Demographics & Architectures
RossiterMcLaughlin, spinorbit alignment, transiting planets

Searching for magnetic star-planet interaction with radio in the CARMENES sample

Poster584Luis Peña-Moñino; IAA-CSIC; Miguel Pérez-Torres; IAA-CSIC

Poster AreaTue 08:30 - 17:50

Sub-Alfvénic interaction between an exoplanet and its host star is expected to yield auroral emission at frequencies of a few hundred MHz and up to the GHz regime, depending on the magnetic field of the host star.

The confirmation of such radio signal would validate radio observations as a new, independent method to discover new exoplanets.

We will present the results from our recent radio campaigns, using the uGMRT (550-950 MHz), of a subsample of CARMENES targets, ranging from Earth-like objects (GJ 486b and GJ 806b) to super-Earths (GJ 436 and GJ 1214). We will discuss the results obtained so far, and how they may guide future observations.

We will also present our latest results on the closest exoplanet to Earth, Proxima b, from a multi-year long campaign using the Australia Telescope Compact Array (ATCA, 1-3 GHz) and MeerKAT (0.9-1.7 GHz) in South Africa.

Star-planet interactions
CARMENES, Radio, SPI

Short-Period Brown Dwarf Companions as a Context for Observing Flare-Driven Photochemistry in Atmospheres

Poster631Aidan Gibbs; University of California, Los Angeles

Poster AreaTue 08:30 - 17:50

Active M Dwarfs produce powerful flares that may impact and erode the atmospheres of planets around them. While this has begun to be explored theoretically, especially for terrestrial planets, the impacts in these planets would be difficult or impossible to directly observe due to the small scale of their atmospheres. In contrast, the atmospheres of hot Jupiters are easier to observe, but few Jovian planets are known around M dwarfs. However, several short-period (<10 day) brown dwarf-M dwarf binaries are known with actively flaring M dwarfs. These contexts may provide an environment with readily observable planet-like atmospheres where flare-driven photochemistry and structural changes can be explored. In this talk, I will present self-consistent photochemical simulations to estimate the impact of flares on brown dwarf atmospheres and the potential observability in high-resolution spectra. I will also discuss observing strategies to mitigate stellar spectral contamination and simultaneously measure flare energies.

Star-planet interactions
planet star interactions, stellar flares

Spectroscopic binning and retrieval sensitivity

Poster612Jack Davey; University College London (UCL)

Poster AreaTue 08:30 - 17:50

With transmission spectroscopy data of higher resolution now being offered by spaced-based observatories such as the James Webb Space Telescope (JWST), it is imperative that we understand the capabilities of our retrieval pipelines. Towards this aim, we present a sensitivity study aiming to quantify the deviation of retrieved parameters from their true values as a function of spectral resolution and observed photometric error. We use simulated WASP-39b transmission spectra across the wavelength range of the NIRSpec PRISM instrument and bin the data to various regimes. We find that caution is warranted when binning to resolutions below R=100 and that the cloud deck in the spectrum heavily influences the resolution to which spectra can be binned for effective retrievals. Further to this, shifts in the wavelength binning grid can introduce significant offsets in the retrieved parameters so the method used to bin spectra is a key consideration.

Atmospheres
Binning, Retrievals

Sub-Neptune populations resulting from magma-atmosphere chemical coupling

Poster777Kaustubh Hakim; KU Leuven / Royal Observatory of Belgium

Poster AreaTue 08:30 - 17:50

Hot sub-Neptunes (equilibrium temperatures > 1000 K) are commonly found in the galaxy. Recent modelling efforts suggest that magma-atmosphere coupling of small exoplanets, i.e., rocky exoplanets and sub-Neptunes, strongly impacts the atmospheric chemistry, enriching the atmosphere in refractory element-bearing gases, e.g., SiO, SiH4. To determine atmospheric chemistry, we implement a new state-of-the-art code, atmodeller, that models an equilibrium chemistry reaction network. Based on the calculations for atmosphere chemistry in the Si-O-H system with mass conservation for H, we can classify sub-Neptune populations into steam worlds, hydrogen worlds, and silicon worlds (see figure). We will further show the strong impact of non-ideal gas behaviour and gas solubility in magma on these populations. These populations should exhibit distinct atmospheric signatures that are detectable with JWST transmission and emission spectroscopy.

Atmospheres
MagmaAtmosphere Coupling, Observable Signatures, SubNeptunes

The 12CO/13CO in directly-imaged planets and brown dwarfs

Poster910Darío González Picos; Leiden University

Poster AreaTue 08:30 - 17:50

The atmospheres of giant planets and brown dwarfs share common spectral features. High-dispersion observations coupled with atmospheric retrievals reveal a wealth of information on chemical abundances and thermo-physical structure. Recently, the 12C/13C isotope ratio has been suggested as a tracer of formation history.

Using the upgraded VLT/CRIRES+ instrument we observe a large sample of giant planets and brown dwarfs with the goal of characterising their atmosphere and measuring the $^{12}$CO/$^{13}$CO isotopologue ratio. I will present results for the substellar companion GQ Lup b/B and a sample of young isolated brown dwarfs.

Atmospheres
directimaging

The challenge of long-period exoplanets: Rossiter-McLaughlin observation of the 542 days period exoplanet HIP41378f

Poster904Salomé Grouffal; Aix-Marseille University

Poster AreaTue 08:30 - 17:50

HIP41378 is a fascinating system hosting at least 5 transiting exoplanets discovered by the K2 mission. HIP41378f (P = 542 days), the outermost transiting planet, has been observed to transit only 5 times. This Saturn-size planet is classified as a 'Super-Puff' due to its unusually low density despite its mild temperature that is not understood. Comparative planetology will be crucial to understand its nature. Since they have a long transit duration and a low transit occurrence, long-period transiting planets are challenging for ground-based characterization. We will present our strategy to observe the 19-h long Rossiter-McLaughlin effect of HIP41378 f collected from the largest worldwide observation campaign. This campaign was set during the unique transit that was visible over the 2020’s decade. We will finally draw important lessons for the future characterisation of long-period transiting planets that will be discovered by the PLATO space mission.

RV and transits
HIP41378, longperiods planets, PLATO, RossiterMcLaughlin

The Coupled Impacts of Atmospheric Composition and Obliquity on the Climate Dynamics of TRAPPIST-1e

Poster702Tobi Hammond; University of Maryland

Poster AreaTue 08:30 - 17:50

Planets in multi-planet systems are expected to undergo gravitational planet-planet interactions which allow them to maintain a non-zero obliquity. The TRAPPIST-1 system is in such a near-resonant configuration, making it plausible that TRAPPIST-1e has a non-zero obliquity. In this work, we use ExoCAM to study the possible climates of TRAPPIST-1e at varying obliquities (0° to 90°) and atmospheric composition (0.0004 bars to 1 bar of CO2). We find that models with a higher obliquity are hotter overall and have a smaller day-night temperature contrast than the lower obliquity models, which is consistent with previous studies. Most significantly, the super-rotating high-altitude jet becomes sub-rotating between 45° and 67.5° obliquity, thus impacting cloud and surface temperature patterns. From modeled thermal phase curves, we find that the impact of obliquity could potentially have observable consequences due to the impact of cloud coverage on the outgoing longwave radiation.

Atmospheres
Terrestrial Exoplanets

The evolution of hot Jupiters revealed by the age distribution of their host stars

Poster548Di-Chang Chen; Nanjing University

Poster AreaTue 08:30 - 17:50

The unexpected discovery of hot Jupiters challenged the classical theory of planet formation inspired by our solar system. Until now, the origin and evolution of hot Jupiters are still uncertain. Determining their age distribution and temporal evolution can provide more clues into the mechanism of their formation and subsequent evolution. Using a sample of giant planets around Sun-like stars, we find that hot Jupiters are preferentially hosted by younger stars in the Galactic thin disk. We subsequently find that the frequency of hot Jupiters declines with age. In contrast, the frequency of warm/cold Jupiters shows no significant dependence on age. Such trends are expected from the tidal evolution of hot Jupiters’ orbits, offering supporting evidence using a large sample. Moreover, the above correlations can explain the bulk of the discrepancy in hot Jupiter frequencies from transit and radial velocity surveys and the null detection of hot Jupiters in globular clusters.

Formation and evolution
planet formation and evolution, starplanet connection

The ExoMol Database: developments and the 2024 data release

Poster961Jingxin Zhang; University College London

Poster AreaTue 08:30 - 17:50

The desire to characterize and model the atmospheres of the many extrasolar planets that have been discovered over the last three decades is a major driver of current astronomy. This goal is impacted by the lack of spectroscopic data for the molecules in question since it requires significant quantities of spectroscopic data, in many cases billions of lines, to accurately reproduce the spectroscopic features of the atmospheres of hot exoplanets.

The ExoMol database provides molecular data for interpreting spectra and modelling atmospheres of hot exoplanets and other hot astronomical atmospheres. The selected molecules are deemed to be important for exoplanets and other studies of hot atmospheres [1]. The core of the ExoMol database is comprehensive high-temperature molecular line lists. The ExoMol line lists are systematically published as a series in the journal Monthly Notices of the Royal Astronomical Society and summarised in four-yearly release papers [2, 3].

Other
ExoMol, exoplanet, line list

The first results from high-resolution transmission spectra of the sub-Neptune GJ 3090b with VLT/CRIRES+

Poster732Luke Parker; University of Oxford

Poster AreaTue 08:30 - 17:50

The enigmatic sub-Neptunes, intermediate in size to Earth and Neptune, have no solar system analogues. Their low bulk densities suggest thick H/He atmospheres surrounding degenerate quantities of iron, silicates, water, and volatiles in solid cores of unknown sizes. To address these compositional degeneracies, we must access their atmospheres, but low-resolution studies have been hindered by clouds or hazes, returning flattened spectra. We present 4 high-resolution CRIRES+ transits of the sub-Neptune GJ 3090b. Orbiting a bright M2 host star on a 2.9-day orbit, GJ 3090b is an ideal target for ground-based study. Searching for molecular species in the K-band we constrain the atmospheric abundances of CH4, H2O, CO, CO2, and NH3 and investigate the properties of clouds and hazes. These observations push two frontiers of high-resolution spectroscopy: 1) advancing to smaller and cooler planets, with lower contrast ratios, and 2) the application of the technique to an M-dwarf host star.

Atmospheres

The first transmission spectrum of TRAPPIST-1c using JWST NIRISS/SOSS

Poster609Jake Taylor; University of Oxford

Poster AreaTue 08:30 - 17:50

The TRAPPIST-1 system has served as a cornerstone system to detect and study the atmospheres of terrestrial planets. The launch of JWST has brought us one step closer to answering the question: do terrestrial planets around M dwarfs retain an atmosphere? In this talk I will present the transmission spectrum of TRAPPIST-1c obtained with NIRISS/SOSS. We observed 2 transits of the planet, spaced one year apart. We assess the consistency between each visit, elucidating the star's impact on the spectrum. We compute an array of atmospheric models and assess what atmospheric or stellar information we can extract from the spectrum.

JWST Results
Atmospheres, TRAPPIST1

The formation of transiting circumplanetary debris discs from the disruption of satellite systems

Poster588Alexander Mustill; Lund University

Poster AreaTue 08:30 - 17:50

Several stars show deep transits consistent with discs of roughly 1 RSol, likely surrounding planets on eccentric orbits. We show that this arises naturally as a result of planet–planet scattering when the planets possess satellite systems. Scattering leads to the exchange of satellites between planets and/or

their destabilisation. This leads to collisions between satellites and their tidal disruption close

to the planet. Both of these events lead to large quantities of debris being produced, which in

time will settle into a disc such as those observed. The mass of debris required is comparable

to a Ceres-sized satellite. Through -body simulations of planets with clones of the Galilean satellite system undergoing scattering, we show that 90% of such systems will possess debris from satellite destruction. Disruption of satellite systems during scattering simultaneously explains the existence of debris, the tilt of the discs, and the eccentricity of the planets they orbit.

Demographics & Architectures
Dynamics, Exomoons

The Impact of possible Orographic Gravity Waves on Rocky Exoplanetary Circulation pattern.

Poster577Leonardos Gkouvelis; Ludwig-Maximilians-Universitat ; Can Akin; Ludwig-Maximilians-Universitat

Poster AreaTue 08:30 - 17:50

Orographic gravity waves play an important role in the vertical coupling between atmospheric layers by redistributing energy, momentum, and, under some circumstances, influencing the large-scale circulation pattern. In this work, we explore the significance of orographic gravity waves on the circulation patterns of rocky exoplanets. Utilizing a modified version of the THOR general circulation model, we simulate diverse scenarios, employing a stochastic approach for topography creation. Our investigation examines the resulting perturbations induced by orographic gravity waves, providing insights into their potential impact on observables. By systematically altering topographic features, we contribute to a comprehensive understanding of the intricate dynamics governing exoplanetary atmospheres and the role that a non-uniform surface boundary plays in their evolution.

Atmospheres
General circulation models, Rocky exoplanets

The impact of rotation and magnetic fields on the radial velocity jitter in cool stars

Poster861Henrik Ruh; Institut für Astrophysik und Geophysik

Poster AreaTue 08:30 - 17:50

Radial velocity (RV) jitter represents an intrinsic constraint on the precision of Doppler searches for exoplanets that can originate from both instrumental and astrophysical sources. We provide a relation between the RV jitter and the stellar equatorial rotation velocity in M dwarfs based on 79 well-characterized stars from the CARMENES survey. Stellar rotation induced RV jitter dominates for stars with equatorial rotation velocities greater than 1 km/s. A jitter floor of 2 m/s dominates in stars with equatorial rotation velocities below 1 km/s. This jitter floor contains contributions from stellar jitter, instrumental jitter and undetected companions. Five stars with excess RV jitter show large average magnetic fields and distinct distributions of magnetic filling factors, characterized by a dominant magnetic field component between 2 to 4 kG. The connection between the RV jitter and magnetic filling factors highlights the role of the magnetic field in the generation of RV jitter.

RV and transits
stars: activity, stars: lowmass, stars: magnetic field, techniques: radial velocities

The impact of stellar spot-crossings on planet transmission spectra

Poster715Catriona Murray; University of Colorado Boulder

Poster AreaTue 08:30 - 17:50

Stellar inhomogeneities are a ubiquitous problem for planets around low-mass stars, often masking or mimicking planetary atmospheric transmission features. Spot-crossing events cause visible chromatic "bumps" in lightcurves related to size and temperature contrasts between star and spot. By spectrally observing spot-crossings, we can empirically derive the starspot's spectrum; key for understanding the unocculted surface and modeling the Transit Light Source Effect. We present chromatic_fitting, which simultaneously fits for planet, spot, and systematics. We demonstrate we can reliably separate spot and planet atmosphere signals injected into simulated JWST datasets and recover the planet's transmission spectrum simultaneously with the wavelength-dependent spot contrast. Our simulations show that marginalizing over the spot's influence increases transit depth uncertainties, which we quantify as a function of spot properties. We also apply our method to real JWST datasets to provide a direct comparison of commonly-used methods of treating stellar contamination (e.g. atmospheric retrievals or integrated out-of-transit spectra).

Star-planet interactions
Cool Stars, JWST, Stellar Contamination

The Occurrence and Architecture of Kepler Planetary Systems as a Function of Kinematic Age

Poster549Di-Chang Chen; Nanjing University; Ji-Wei Xie; Nanjing University

Poster AreaTue 08:30 - 17:50

In the fourth paper of the Planets Across Space and Time (PAST) series, we investigate the occurrence and architecture of Kepler planetary systems as a function of kinematic age. We find, (1) Nearly 50% of stars host Kepler-like planets (Fkep) across all ages. (2) The average planet multiplicity (Np) decreases from ~3 for stars under 1 Gyr to ~1.8 for stars about 8 Gyr. (3) Number of planets per star (η=Fkep*Np) decreases from ~1.6--1.7 for young stars to ~1.0 for old stars. (4) The mutual orbital inclination of planets (σi,k) increases from 1.2+1.4-0.5 to 3.5+8.1-2.3 as stars aging with a best fit of log(σi,k)=0.2+0.4*log( Age/1Gyr). Interestingly, the Solar System aligns with this trend. The nearly independence of Fkep~50% on age implies planet formation is robust and stable across the Galaxy history. However, Np and σi,k dependence on age indicates evolving planetary architectures, tending toward systems with fewer, dynamically warmer planets.

Demographics & Architectures
Planetary systems, Planetstar interactions, Statistical

The Paranal solar ESPRESSO Telescope - towards a resolved view of the Sun

Poster891André M. Silva; Instituto de Astrofísica e Ciências do Espaço

Poster AreaTue 08:30 - 17:50

High resolution spectroscopy plays a key role in the effort to detect and characterise other Earths. This objective remains challenged by astrophysical signals introduced from their host stars, severely challenging the detection and characterisation of exoplanets similar to our Earth. An analysis of our closest star, the Sun, might shed light into the origins of such signals. However, there is no instrumentation capable of analysing the contribution of each solar feature.

The Paranal solar ESPRESSO Telescope (PoET) will cover this gap, with its first light planned for 2025. It will connect to the ESPRESSO spectrograph (ESO-VLT), acquiring both disk-resolved and disk-integrated ("sun-as-a-star") observations of the Sun. This dataset will be obtained in the ultra-high resolution mode (R>200 000), covering the full optical domain (380-780 nm) in one single shot. In the behalf of the PoET team, I will present the instrument, its scientific goals and the observation strategy.

Future missions/instrumentation
Instrumentation, Solar telescope

The PPOLs Model of Pebble Accretion for Water Delivery to Inner Planet Cores

Poster689Sean McCloat; University of North Dakota

Poster AreaTue 08:30 - 17:50

A key area linking frontier observational capabilities to theoretical questions of exoplanet system architectures is the transport and evolution of water in planet-forming disks and mechanisms that tune its incorporation into planets. This research develops a pebble accretion model of planet formation (“the PPOLs Model”) that self-consistently handles the drift and accretion of rocky/icy pebbles around stars ranging from late M-dwarfs to early A-stars. The model grows multiple protoplanet cores simultaneously and evolves the snowline position consistently with evolving disk conditions. The combination of growing multiple cores while evolving the snowline allows for a prolonged period of growth and delivery of icy pebbles to the inner disk. Results explore water content in the habitable zone across the stellar mass range, and under which conditions systems resemble the Solar System or Kepler systems, ultimately connecting the formation conditions of stellar/disk properties and seed mass distribution to system architectures.

Demographics & Architectures
system architecture

The quest for the He I 10830 triplet in exoplanets

Poster769Jorge Sanz-Forcada; Centro de Astrobiología, CSIC-INTA

Poster AreaTue 08:30 - 17:50

Exoplanet atmospheres photoevaporate because of XUV stellar irradiation. Evaporation signs are detected through the H Lyman alpha line, or more recently in the He I 10830 triplet. The stellar high energy irradiation also plays a role in this line formation, but no direct observation of most of XUV spectral range is possible in stars other than the Sun. We present an update of the X-exoplanet database, and improved scaling laws that take into account the stellar activity level. We also explore the expected relation between stellar XUV irradiation at the planet, calculated with the best coronal models available, and the measurements of the He I 10830 line at planet atmospheres reported to date. The new scaling laws and X-exoplanet models can be widely used to interpret the planet atmosphere spectral features.

Atmospheres
Extreme Ultraviolet Astronomy, planet atmospheres, stars: coronae

The Role of Orbital Dynamics In Planetary Habitability

Poster804Stephen Kane; University of California, Riverside

Poster AreaTue 08:30 - 17:50

A key component of characterizing multi-planet exosystems is testing the orbital stability based on the observed properties. Orbital dynamics is also a critically important component of testing habitability scenarios for terrestrial planets within the system, and can play a major role in driving the evolution of terrestrial planet climates. In this presentation, I will describe recent work regarding the effects of orbital dynamics on planetary habitability, including the effect of giant planets on terrestrial planet orbital stability and volatile delivery, dynamical limits on Habitable Zone terrestrial planets, and global circulation models that demonstrate the climate impacts and water loss rates for eccentric orbits. I will discuss examples of orbital dynaimcal effects on habitability, including the HR 5183, HD 141399, and Beta CVn systems. This work emphasizes the need for refining Keplerian orbits as a crucial input for climate studies and the potential impact of eccentricity on terrestrial planet surface conditions.

Habitability
orbital dynamics, planetary habitability

The Rossiter-McLaughlin effect and exoplanet transits: a delicate association at medium and low spectral resolution.

Poster669Yann Carteret; Observatoire Astronomique de l’Université de Genève

Poster AreaTue 08:30 - 17:50

The characterization of exoplanetary atmospheres via transit spectroscopy is based on the comparison between the stellar spectrum filtered through the atmosphere and the unadulterated spectrum from the occulted stellar region. The “Rossiter-McLaughlin” (RM) effect is known to bias transmission spectra at high spectral resolution, however its specific effect is less understood at lower resolution. We found that the RM effect should not bias broadband atmospheric features, such as hazes or molecular absorption, measured with the JWST/NIRSPEC (prism mode) at low resolution. However, absorption signatures from metastable helium or sodium measured at medium resolution with the JWST/NIRSPEC (G140H mode) or HST/STIS can be biased, especially for planets on misaligned orbits across fast rotators. In contrast we show that the signature measured by Charbonneau et al. (2002) in an aligned system cannot be explained by the RM effect, supporting a planetary origin.

Atmospheres
HD209458b, Low resolution spectroscopy, RossiterMcLaughlin

The stability of water-rich atmospheres

Poster537Antonio García Muñoz; CEA Paris-Saclay

Poster AreaTue 08:30 - 17:50

The young Earth and Venus likely had water-rich atmospheres, a possibility that has been extensively explored to understand the planets’ histories. Amongst the known population of sub-Neptune-sized planets, it is believed that many of them have accumulated large amounts of water. If the idea is true, some of that water might still reside in the thick envelopes that these planets have. Understanding the stability of water-rich atmospheres is therefore key to tracing the origin and evolution of the small worlds that are being discovered. Although the stability of H2/He-dominated atmospheres has been treated extensively, much less work has been done for water-rich atmospheres. Water however is expected to react very differently to stellar radiation due to its specific collisional-radiative properties. We are developing the theory to describe those microphysical processes. This talk will summarize the project status, emphasizing the role of H2O NLTE in the long-term stability of water-rich atmospheres.

Atmospheres
escape, longterm, stability

The Uncharted Worlds JWST Direct Imaging Survey for Sub-Jupiter Mass Exoplanets

Poster801Aarynn L Carter; University of California, Santa Cruz

Poster AreaTue 08:30 - 17:50

The wavelength coverage of JWST, alongside it's exquisite sensitivity and stability, provides an unrivaled opportunity to directly image exoplanets of lower masses than ever before. In this talk, we will present the first results from the Uncharted Worlds program - the largest JWST direct imaging survey to date. Our survey is sensitive to sub-Jupiter, and even sub-Saturn mass companions at wide separations beyond 20 au. Prior to JWST, this parameter space remained almost entirely unexplored, as most ground-based observations are only sensitive to more massive, super-Jupiter, companions. As such, our program provides the first empirical constraints on sub-Jupiter exoplanet occurrence at wide separations, which itself is closely connected to our understanding of planetary formation and evolution, and the nature of debris disk spatial structures. Finally, discoveries from this program will act as new atmospheric benchmarks, and will serve as unique comparisons to existing transiting, directly imaged, and Solar System planets.

JWST Results
JWST, SubJupiters

Three temperature radiation hydrodynamics with PLUTO: planet induced rings, gaps, and shadows in disks

Poster690Dhruv Muley; Max-Planck-Institut für Astronomie

Poster AreaTue 08:30 - 17:50

In a circumstellar disk, angular momentum exchange between a nascent planet and surrounding gas carves a gap near the planetary orbit, with the excavated material forming a prominent, dust-trapping exterior ring visible in millimeter continuum. As the quality of observations improve, it is important to understand the how the underlying physics---particularly thermodynamics---shapes their morphology. To this end, we simulate disk-planet interaction in 3D with the PLUTO code, comparing a parametrized beta-cooling prescription to a more sophisticated "three-temperature" scheme that accounts for energy exchange between gas, dust, and radiation. With the latter scheme, we find that stellar irradiation induces a low-number azimuthal instability at the outer edge of a sufficiently deep gap. The resulting shadows may help explain time-varying non-axisymmetries observed in systems such as HD 100456 and TW Hya.

Formation and evolution
protoplanetary disks, radiative transfer

TOI-2015 b: A sub-Neptune-desert planet around an M-dwarf star with large TTVs

Poster564Khalid Barkaoui; Astrobiology Research Unit, Université de Liège, Allée du 6 Août 19C

Poster AreaTue 08:30 - 17:50

Transit timing variations (TTVs) can be used to search for additional non-transiting exoplanets and estimate their physical parameters. Here we report the spectroscopic (MAROON-X) and photometric (TESS & ground-based) confirmation of TOI-2015b, which is a sub-Neptune-desert planet orbiting around an M4-type metal poor star ([Fe/H]= -0.31) in 3.35 days. TOI-2015b has a mass of Mp = 4.7+/-0.4M_earth and a radius of Rp=3.74+-0.12R_earth. Its transits exhibit large TTVs indicative of an outer perturber in the system. Our analysis places the second planet near the 5:3 resonance with a period of Pc = 5.785 days and a mass of Mp = 11.2+/-0.6M_earth. The dynamical configuration of the orbits of TOI-2015b and TOI-2015c can be used to constrain the planetary formation and migration history of the system. Moreover, TOI-2015b has a high transmission spectroscopy metric (TSM = 250), making this planet an excellent target for future atmospheric exploration with JWST.

RV and transits
Photometry, Radial velocity, TTVs

TOI-332b: a super dense Neptune found deep within the Neptunian desert

Poster611Ares Osborn; McMaster University

Poster AreaTue 08:30 - 17:50

Though we have confirmed the existence of thousands of planets, there remain unpopulated regions of period-radius-mass parameter space; for example, the Neptunian desert, where planets should be easy to find but detections are few. As part of the “Nomads” programme performing precise RV follow-up of TOIs in the Neptunian desert, we present TOI-332b, an ultra-short period planet located deep within the desert. With a radius smaller than Neptune, but an unusually large mass of more than half that of Saturn, it is one of the densest planets discovered thus far. Internal structure modelling predicts a likely negligible H/He envelope mass fraction, but photoevaporation cannot account for the mass-loss required to strip this large core of the envelope it would have been expected to accrete. We look towards other scenarios, like giant impacts, high eccentricity migration, and gap opening in the protoplanetary disk, to explain this unusual discovery.

RV and transits
Planet discovery

Towards Transiting Tatooines: A search for circumbinary planets with TESS

Poster812Dominic Oddo; University of New Mexico

Poster AreaTue 08:30 - 17:50

Circumbinary planets (CBPs; planets orbiting outside of both stars in a tight stellar binary) represent an exciting frontier in exoplanet research. CBP discoveries yield deep troves of information, providing rich insights into each system we find. However, with a small sample of only 14 transiting CBPs so far, we cannot yet tell a complete story of CBPs. There are many mysteries regarding CBP formation and evolution which are yet to be addressed, including reliably explaining how CBPs form. By finding more CBPs, we will learn more about the limits of planet formation and the extremes of planetary system architectures. We are searching for transiting CBPs in the light curves of many eclipsing binaries (EBs). We describe here our search methods, including the masking of EB signatures and the identification of transit events. We further discuss candidate CBP detections to date and future steps towards validating these candidates.

Demographics & Architectures
Circumbinary planets

Transit Photometry at the Wendelstein Observatory

Poster949Laura Schöller; University Observatory Munich

Poster AreaTue 08:30 - 17:50

We present the capabilities of the Wendelstein Observatory for photometric transit detections of exoplanets. The Wendelstein Observatory operated by the Universitäts-Sternwarte of the Ludwig-Maximilians University Munich, contributes to the search for exoplanets as part of the TESS Follow-up Observing Program Working Group for Photometry (TFOPWG SG1). The observatory houses the 2.1m Fraunhofer Telescope Wendelstein (FTW), the largest optical telescope in Germany, and a 43cm telescope. The FTW is equipped with a wide field imager (WWFI) for precise measurements in various optical filters and a three-channel-camera (3KK) for simultaneous multi-band observations in a blue, red, and near-infrared filter covering a wavelength range from 0.35 to 2.4 μm. Both instruments can detect shallow transit events below 1 ppt and offer a pixel scale of 0.2 arcsec/pixel. Over the last few years, the Wendelstein Observatory has provided more than one hundred transit detections.

RV and transits
multiband photometry, TESS followup

Transiting giant planets around low-mass stars

Poster601Yolanda Frensch; Geneva Observatory

Poster AreaTue 08:30 - 17:50

Core-accretion models predict that giant planets orbiting low-mass stars are rare and suggest that the occurrence should decrease to zero for the stellar mass range of 0.7-0.3MSun. However the occurrence is not equal to zero, as these rare companions have been detected via transit surveys and confirmed by radial velocity. We present two TESS radial-velocity follow-up programs using NIRPS and CORALIE spectrographs to search for giant planets around low-mass stars (Teff<4500K). We report newly discovered transiting giant planets and brown dwarfs, along with the observed false positive rate within our subsamples. Through these two programs, we aim to increase the population statistics and study the turning point in giant planet formation from early K to late M dwarfs (which includes already known planets outside our sample). These two aspects are necessary to better understand the formation and evolution mechanisms of giant planets.

RV and transits
Giant planets, Lowmass stars

Two of a kind: parallel transmission spectra of a single transit

Poster536Dominique Petit dit de la Roche; University of Geneva

Poster AreaTue 08:30 - 17:50

Interpretation of ground-based transmission spectra is complicated by systematic uncertainties, especially at low to medium resolutions. In this talk we compare two ground-based medium-resolution transmission spectra (R~5000) of WASP-69b taken independently of the same transit with different telescopes at different sites. We discuss the non-detection in our FORS/VLT dataset of the potential TiO signature from SOAR/GHTS and show the dependence of the spectral shape on the chosen fitting parameters, as well as give an overview of the CHEWIE survey of which our transmission spectrum is the first result.

Atmospheres
Groundbased, Observation, Transmission spectrum, WASP69

Ultraviolet to Infrared Atmosphere Spectroscopy of the Hot-Neptune LTT 9779b

Poster838Michael Radica; Université de Montréal

Poster AreaTue 08:30 - 17:50

The manner in which planets can manage to survive in the inhospitable region known as the hot-Neptune desert is one of the most keenly researched question in exoplanetary science. In recent years, the roughly 1.5 Neptune-mass and T~2300K planet LTT 9779b has become the quintessential target for studies of hot-Neptunes. In this talk, we will present a unified ultraviolet to infrared atmosphere study of this keystone target using transit observations from JWST NIRISS/SOSS and eclipse observations from SOSS as well as HST/UVIS. Our work reveals the presence of clouds in an extremely metal-enriched and non-thermally-inverted atmosphere. We assess the extent to which feedback from high-albedo clouds can suppress the emergence of a day-side thermal inversion, while simultaneously prolonging the lifetime of LTT 9779b’s atmosphere.

JWST Results
Atmosphere, Hot Neptune, HST, JWST

Uncovering the Obliquity Distribution of Hot Stars with Massive Hot Jupiters and Brown Dwarfs

Poster851Steven Giacalone; California Institute of Technology

Poster AreaTue 08:30 - 17:50

Hot stars are known to have spins that are frequently misaligned with the orbits of their hot Jupiters. These high "stellar obliquities" are thought to be a consequence of either (1) dynamical interactions between the planets and massive outer companions or (2) primordial misalignments between stars and their protostellar disks. While these mechanisms can produce similar outcomes, they differ in one important way: the former becomes less efficient at creating misaligned systems with increasing planet mass, whereas the latter does not. Currently, the vast majority of hot Jupiters with these measurements are low in mass, largely because super-Jovians and brown dwarfs in close-in orbits are rare and are therefore found mostly around faint stars. To disentangle these processes, we are undertaking a survey to measure the obliquities of hot stars with massive transiting companions using the Keck Planet Finder spectrograph. In this talk, we present early findings from our survey.

Demographics & Architectures
Hot Jupiters, Stellar obliquity

Understanding the Planetary Formation and Evolution in Star Clusters(UPiC)

Poster578Yuan-Zhe Dai; Nanjing University

Poster AreaTue 08:30 - 17:50

Planets in young star clusters could shed light on planet formation and evolution since star clusters can provide accurate age estimation. The UPiC project aims to find observational evidence and interpret how planets form and evolve in cluster environments. In this work, we cross-match the stellar catalogs of new OCs with confirmed planets and candidates. We obtained the biggest catalog of planets in star clusters up to now, which consists of 73 planets and 84 candidates. We find an increment of Hot Jupiters(HJs) fraction around 100 Myr and attribute the increment to the flyby-induced high-e migration in star clusters. An additional small bump of the fraction of HJs after 1 Gyr is detected, which indicates stellar environments play important roles in the formation of HJs. The Hot-Neptune desert occurs around 100 Myr in our sample. Combining photoevaporation and high-e migration may sculpt the Hot-Neptune desert in clusters.

Formation and evolution
Exoplanet catalogs, Exoplanet evolution, Open star clusters

Unmasking stellar activity in extreme precision Doppler spectroscopy using Neural Networks

Poster655Jordi Blanco-Pozo; Institute of Space Sciences (ICE-CSIC)

Poster AreaTue 08:30 - 17:50

In the exoplanetary field, instrumental precisions have already reached levels below the jitter introduced by magnetic activity of the stellar hosts. This affects the detection of exoplanets, the measurement of their radii, and the analysis of their atmospheres. With the focus on modern high-resolution spectrographs, space-based imagers like JWST, or the future ARIEL mission, the mitigation of those effects is crucial for the advancement of the field.As a continuation of a long term effort developed by our group, I will present an approach using state-of-the-art machine learning techniques in the form of deep neural networks to “clean” observational data from the influence of stellar noise. As training data, we use synthetic observables of spotted rotating stellar hosts using the STARSIM code, including photometry, spectroscopic observables and cross-correlation functions. I will outline the results we have obtained so far for this project including the application to real observational data.

RV and transits
Machine Learning

Unraveling the Dust-Gas Dynamics in the Rings of Protoplanetary Disks

Poster539Maya Tatarelli; McGill University

Poster AreaTue 08:30 - 17:50

Radio interferometric images have revealed that concentric dust rings are a common feature of protoplanetary disks. These rings are areas of high density and consequently, are thought to be potential sites for planetesimal, and eventually planet, formation. How efficiently the dust grains collect into these rings is dependent on both the source of pressure perturbations that trap the dust and the size of the grains themselves. We report on this dust trapping efficiency using multi-dimensional GIZMO simulations of protoplanetary disks with an embedded planet that creates dust traps, varying planet mass and particle Stokes numbers. Using the measured trapping efficiency, we will provide some initial calculations on the collapse and mass growth of dust clumps within the rings at varying orbital distances.

Formation and evolution
Dust ring formation, Dustgas fluid interaction, Hydrodynamic simulations

Unraveling the influence of atmospheric escape on heavy metal evolution in warm (super-)Neptunes

Poster663Amy Louca; Leiden University

Poster AreaTue 08:30 - 17:50

Planetary migration leads to the accretion of heavy atoms in solid form during planet formation. This gives a change in metal ratios, such as the C/O ratio, in atmospheres. Observations have shown that the metal abundance of atmospheres is indeed different compared to their host star composition. These observations are, however, biased towards mature planets, which raises the question of whether this observed heavy metal abundance is an imprint from formation or actually changed over time. One way to alter an atmosphere is through the escape of particles due to thermal heating. In this work, we look at how Gyrs of particle escape affects the relative metal abundances. Our results show a sulfur enhancement of ~6% compared to other metals on warm Neptunes. We show that a combination of formation and evolution is needed to explain the observed features that we see today, putting strong constraints on formation processes.

Formation and evolution
Atmospheric simulations, Gaseous exoplanets

Unravelling the atmospheres of rocky planets with real gas equations of state and solubility

Poster855Dan Bower; ETH Zurich

Poster AreaTue 08:30 - 17:50

Observations of rocky exoplanets require a quantitative understanding of the factors that control the nature and composition of atmospheres. The speciation of major atmosphere-forming components around molten planets is dictated by their abundances, equilibrium chemistry between gas species, and solubilities in the rocky interior. Moreover, gas phases become non-ideal at high pressure. We combine these considerations into a new Python package (atmodeller), which computes the equilibrium conditions at the melt-atmosphere interface of super-Earths and sub-Neptunes. Given a set of planetary parameters and an initial volatile budget, atmodeller uses experimentally calibrated solubility laws, together with free energy data for condensed and gas species, to determine how volatiles partition between the atmosphere and interior of the planet. Within the H-C-N-O-S-Cl system, we investigate the diverse range of atmospheric compositions and the impact of volatile dissolution into the interior for select exoplanets based on JWST observational constraints, including the TRAPPIST-1 system and K2-18b.

Atmospheres
interioratmosphere coupling, real gas eos, solubilities

Unsupervised reduction and sensitivity analysis of astrochemical networks for exoplanets

Poster806Arturo Lira Barria; KU Leuven

Poster AreaTue 08:30 - 17:50

The field of exoplanet atmospheric modelling is moving in the direction of more complex coupled circulation - chemistry models, including Global Circulation Models (GCMs). However, the chemical diversity contained within these models often has to be very limited due to the computational expense of GCMs. Lower-dimensional 1D and 2D models, for which computational expense issues are less severe, can be used to assess the accuracy of reduced chemistry networks by comparison to more extensive ones. However, there are as yet no systematic procedures to extract such reduced networks. We suggest a transparent, systematic and unsupervised approach based on a sensitivity analysis of a typical 1D-model, and use this to construct reduced networks for a variety of scenarios for exoplanets. Additionally, we explore ways for assessing the accuracy of those networks.

Atmospheres
Astrochemistry, Atmospheres, Numerical methods

Unveiling the internal structure of the three planets transiting HIP 29442 with CHEOPS

Poster587Jo Ann Egger; Weltraumforschung und Planetologie, Physikalisches Institut, Universität Bern

Poster AreaTue 08:30 - 17:50

We present new CHEOPS data for the two inner super-Earths (P=3.5 and 6.4 days) and one outer sub-Neptune (P=13.6 days) of the compact HIP 29442 system, allowing us to significantly improve the radius precision of all three planets. Together with the very precise masses from Espresso [1], this makes HIP 29442 an ideal system to probe the internal structure of its planets. As there are always multiple compositions that can explain the observed mean density of a planet, we apply Bayesian inference to obtain probability distributions for each planet's internal structure. We developed a new and improved internal structure framework that allows us to model each planet with either separate water and H/He layers or a uniformly mixed water and H/He envelope. In addition, we studied possible formation and evolution pathways of the system by comparing it to synthetic systems produced with the latest version of the Bern model [2].

RV and transits
Planetary systems, Planets and satellites: interior, Planets and satelllites: formation

Unveiling young exoplanet atmospheres with high dispersion spectroscopy

Poster881Jiacheng Peng; Department of Physics and Astronomy, University of Bologna

Poster AreaTue 08:30 - 17:50

Characterising the properties of young planets embedded in protoplanetary disks is critical to understanding the formation of exoplanets, their atmospheres and their evolution. High-contrast imaging and indirect gas kinematics evidence have led to the detection of several young planet candidates. Observing the atmospheric emissions from those objects using state-of-the-art high-resolution spectroscopy conducted with Adaptive Optics (HDS + AO) has become the next important step.The capabilities of HDS+AO have not been fully explored yet. We introduce the pipeline EXOCRIRES for synthetic observations of exoplanets with CRIRES+ on VLT. Our goal is to assess the feasibility of observing young, directly-imaged planets across various physical configurations. Analysis shows the potential of HDS observation on different planetary systems to retrieve multiple molecular emissions.Moreover, the pipeline can be adapted to different atmospheric models and telescopes including ELT, as a versatile tool for pathfinder research of exoplanets in the emerging era with ANDES.

Atmospheres
Highdispersion Spectroscopy, Planet Atmosphere, Young Planet

Variability and Spectroscopic Modeling of Brown Dwarf Atmospheres

Poster731Xianyu Tan; Shanghai Jiao Tong University

Poster AreaTue 08:30 - 17:50

The atmospheres of most brown dwarfs (BDs) and directly imaged exoplanets are sculpted by the internal heat flux, providing valuable testbeds to understand the climates of self-luminous objects. Variability is common among these objects with a small fraction having exceptionally large variability amplitudes. JWST spectroscopic time-series observations will lead to further breakthrough discoveries. Our recent theoretical development suggested that cloud radiative feedback leads to a self-sustained dynamical system that generates large-scale turbulence and traveling waves, producing variability with morphology and amplitudes that could broadly explain some of the observed variability. Using an updated nongrey model, we simulate VHS1256b, the most variable BD detected so far, as a template to illustrate how we can use spectrum and variability simultaneously to constrain the atmospheric properties. We will also show how varying rotation would lead to systematic variation in the overall spectral properties, near-IR colors, and variability amplitudes.

Atmospheres
Brown Dwarf, Giant Planet, Spectrum

WASP-193b: The lightest hot Jupiter ever found

Poster887Francisco J. Pozuelos; Instituto de Astrofísica de Andalucía-CSIC

Poster AreaTue 08:30 - 17:50

Transiting gas giants provide insights into planetary system formation and evolution mechanisms. Most of these planets serve as benchmarks for our understanding of planetary systems. However, outliers offer unique opportunities to explore unconventional formation and evolution processes. This talk presents WASP-193b, one of the lightest planets ever discovered, the lightest in the hot-Jupiter population. We found that WASP-193b has a mass of 0.139 MJupiter and a radius of 1.464 RJupiter, translating into an extremely low density of 0.059 g/cm3, remarkably less dense than typical gas giants. The combination of its large transit depth, extremely low density, high-equilibrium temperature, and the infrared brightness of its host star make WASP-193b an exquisite target for characterization by transmission spectroscopy. One single JWST transit observation would yield detailed insights into its atmospheric properties, providing a unique window to explore the mechanisms behind its exceptionally low density and shed light on giant planets' diverse nature.

RV and transits
HotJupiter, JWST

WASP-69b: global modelling of helium escape as seen with NIRPS

Poster661Yann Carteret; Observatoire Astronomique de l’Université de Genève

Poster AreaTue 08:30 - 17:50

Recently the metastable helium triplet line (∼10833Å) proved a powerful tracer of highly irradiated and expanding upper atmospheres. We present observations of helium absorption from WASP-69b by the NIRPS instrument. The helium light-curves show post-transit absorption, suggesting the presence of a cometary tail formed by the escaping atmosphere. We perform a global analysis of the system, first analyzing the Rossiter-McLaughlin signal induced by the planet, and then using the derived orbital architecture to interpret the helium transmission spectra with a self-consistent model of the star and planet. To do so we perform three dimensional simulations of the transit with the EVE code, taking into account the geometry of the transit and the effects induced by the occultation of the stellar surface. Our study refines the system spin-orbit angle and planetary mass-loss, and sets a standard procedure to interpret helium absorption signatures.

Atmospheres
Helium, HighResolution Transmission Spectroscopy, NIRPS, Photoevaporation

Wave propagation and transmission in a rotating polytropic spherical shell

Poster721Yuru Xu; Beijing Normal University

Poster AreaTue 08:30 - 17:50

Wave propagation can transport momentum and energy, therefore it may have significant impact on stellar or planetary structures and evolutions. It is quite common for a star or planet to have a multi-layer structure, and yet propagation and transmission of internal waves in these layers have not been fully explored. In this work, we study the wave propagation and transmission by solving the linearized equations of a compressible, self-gravitating, uniformly rotating polytropic spherical shell. The Coriolis force is fully taken into account but the centrifugal effect is neglected. We characterize the energy flux and kinetic energy of these waves and find that energy flux carried by high-frequency acoustic wave but kinetic energy carried by low-frequency gravity wave, inertial wave or mixed gravito-inertial wave (GIWs). It is also shown that rotation can facilitate wave propagation and enhance wave transmission.

Formation and evolution
Internal waves, Planetary interiors, Rotation

What PDS 70 can tell us about hot- and cold-start formation models

Poster746Jonas Sauter; Max Planck Institute for Astronomy

Poster AreaTue 08:30 - 17:50

The PDS 70 system is unique in that two planets, PDS 70 b and c, have been detected inside a protoplanetary disc. Young planetary systems such as this one give us important information about hot-, warm- and cold-start planet formation models, since the luminosity predicted by these models diverges towards low system ages. However, a precise planetary mass is required to associate a planet with a given formation model. The previous mass estimates of PDS 70 b and c by Wang et al. (2021) have a 95% confidence interval spanning almost the entire range of the uniform prior used (1-15 MJup). Using new astrometry data from the GRAVITY instrument of the VLT, we have been able to significantly reduce the uncertainty on these mass estimates.

Direct Imaging and Interferometry
Exoplanet formation, PDS 70

When do planetary systems become debris disks?

Poster729Carsten Dominik; University of Amsterdam

Poster AreaTue 08:30 - 17:50

Many young planet-forming disks show cleared-out inner regions, most likelt because a planetary system already exists in these regions. Nevertheless, many such disks contain a low mass dust component quite close to the star, showing up in observations as near-infrared excess (meeus 2001) and as inner disks producing shadows in scattered light images on the outer disk (Benisty+2023). The question on how this dust is maintained for a long time in this region where it should be quickly accreted to the star has bee a question for many years (Pinilla+2016). In this contribution we will how that such a dust component can be created by collisions between planetesimals in a disk that is not yet devoid of gas. The conclusion is that these very young systems are already transitioning to be debris disks. Such a model provides constraints on the architecture and sub-planetary mass content in those systems.

Demographics & Architectures
Planetary systems

XO-7 as a possible multi-object planetary system characterized with TESS and MUSICOS/SP

Poster563Zoltán Garai; HUN-REN-ELTE Exoplanet Research Group

Poster AreaTue 08:30 - 17:50

XO-7b is a hot Jupiter transiting a V = 10.52 mag G0V-type star. The planetary system is interesting because the linear slope in the discovery radial-velocity (RV) data indicated a wide-orbit massive companion. In 2020 we started an RV campaign for the system with the main scientific goal to follow-up this linear slope, and to put constraints on the orbital period of the companion. The previously observed significant linear RV slope was not confirmed with the follow-up RV data, where we detected only a marginal linear slope with the opposite trend. If the announced companion really exists, the most convincing explanation is that both RV datasets were collected near its quadrature position. Based on the RVs we estimated the minimum orbital period, and the ‘minimum’ minimum mass of the companion. We did not find significant evidence of the companion of XO-7b in the observed-minus-calculated (O-C) dataset of mid-transit times.

RV and transits
methods: observational, planets and satellites: individual: XO7b, techniques: photometric, techniques: radial velocities

Your Opportunities with ESA's CHEOPS

Poster976Theresa Luftinger ; ESA/ESTEC; Ana Heras; ESA

Poster AreaTue 08:30 - 17:50

The European Space Agency’s (ESA’s) CHaracterising ExOPlanet Satellite (CHEOPS) is the first space mission dedicated to the search for exoplanetary transits through high-precision photometry of bright stars already known to host planets. The mission enables precise radius measurements for small (e.g., super-Earth and sub-Neptune) exoplanets, mass determinations for systems with transit timing variations, and the atmospheric characterisation of highly irradiated companions. Recent CHEOPS science highlights include two six-planet systems with resonant orbits, a rugby-ball-shaped hot Jupiter, phase curves of lava worlds, a highly reflective atmosphere, and even rings around trans-Neptunian objects. CHEOPS has recently completed its 3.5-year-long Nominal Mission and successfully transitioned into its first Extended Mission, providing the community with even more opportunities to get involved and apply for observing time. Come discuss your ideas and submit your proposals!

Other
CHEOPS, ESA, Photometry

09:30 - 10:30 Plenary Talks 3

2. The Biggest Eye on the Sky: the time-resolved winds of WASP-121b in ESPRESSO’s 4UT mode

Plenary Talk73Julia Victoria Seidel; European Southern Observatory

Grote ZaalTue 09:30 - 10:30

The groundbreaking ESPRESSO 4UT mode boasts the world's largest photon-collecting power with a virtual 16-m class telescope simulating a mini-ELT. We present an observational study leveraging this mode of the ultra-hot Jupiter, WASP-121b. Existing observations of a partial transit unveiled a time-resolved jet stream in the planet's atmosphere for the first time (see Seidel et al. 2023). Notably, the absence of ingress data has left the critical question of whether this phenomenon results from a super-rotational jet or day-to-night side winds unanswered.Here, we present for the first time the missing ingress dataset observed in September 2023 (Seidel et al. 2024, in prep.). Our findings complete the first time-resolved dataset on an ultra-hot Jupiter crucially revealing the atmospheric dynamics resolved across the planet’s visible atmosphere. This one-of-a-kind dataset provides a stringent test for theoretical Global Circulation Models and will be crucial in the ramp-up for the ELT era.

Atmospheres
atmospheric dynamics, highresolution spectroscopy, timeresolved

3. Exoplanet Interiors in the JWST Era

Plenary Talk1135Daniel Thorngren; Johns Hopkins University

Grote ZaalTue 09:30 - 10:30

Spectroscopic studies of giant planets with JWST have focused on determining the C/O ratio and atmospheric metallicities. The latter not only provides direct information on the planet’s composition, but also synergizes with bulk metallicities to provide a window into the deep interior. For example, if significantly more metals are seen in the bulk than the atmosphere, it implies that the planet is compositionally differentiated. I’ll highlight exciting new results from WASP-107 b JWST observations that indicate a very hot interior, tidal heating, and the presence of a core, as well as JWST results for WASP-39 b confirming its extremely metal-rich nature. I’ll also show how this analysis can also be applied to directly-imaged planets in cases where the log(g), radial-velocity, or astrometry data constrains the mass (e.g. HR 8799 e). These will allow us to better constrain exoplanet interiors and formation histories than was previously possible.

Interiors
Interiors

4. Chemical Signatures of Embedded Protoplanets in Planet-forming Disks

Plenary Talk1039Charles Law; University of Virginia

Grote ZaalTue 09:30 - 10:30

ALMA has revealed ubiquitous dust gaps in protoplanetary disks, which suggests that planet formation is well underway. Despite this, it remains difficult to unambiguously connect individual substructures with the location and properties of nascent planets. Since embedded planets locally heat the disk, sublimate volatile-rich ices, and produce gas shocks, molecular-line observations can uniquely trace the earliest stages of planet formation. Here, we present the discovery of the most compelling set of planet-induced chemical signatures to date in the giant-planet-hosting HD 169142 disk. This includes the first detection of SiS in a disk and implies that the HD 169142 b planet is driving strong shocks. We also discuss ongoing observational follow-up, including an ALMA molecular survey around the planet location and a deep VLA search for associated free-free emission. Overall, this discovery shows that observations of shock-tracing molecules provide a novel approach to the detection and characterization of young, embedded planets.

Formation and evolution
ALMA, Planet formation, Protoplanetary disk

11:30 - 12:00 Plenary Talks 4

1. A Hell of a Phase Curve: Mapping the Thermal Emission of the Lava Planet K2-141b

Plenary Talk1303Lisa Dang; Université de Montréal

Grote ZaalTue 11:30 - 12:00

Lava planets are ultra-short-period planets with bulk densities consistent with terrestrial composition, but dayside temperatures hot enough to melt—and vaporize—rock. Of these planets, the most favorable candidate for atmospheric and surface characterization is the super-Earth K2-141b with a density of 8 g/cm^3 and an orbital period of 6.7 hrs around a J=9 star. Spitzer and K2 photometric phase curves of K2-141b hints at a tenuous rock vapor atmosphere. We present the full-orbit spectroscopic MIRI/LRS (5-12 um) phase curve of K2-141b to map the planet’s thermal emission as a function of longitude. In addition to constraints on the phase offset, Bond albedo, and heat recirculation efficiency from the phase curve, the emission and transmission spectra provide further evidence into the presence, or lack-of a global atmosphere on a lava planet.

JWST Results
lava planets

2. A radius valley between migrated steam worlds and evaporated rocky cores

Plenary Talk299Remo Burn; Max Planck Institute for Astronomy

Grote ZaalTue 11:30 - 12:00

We present a model for the radius valley, using population syntheses. Conventially, it is explained by the loss of primordial H/He envelopes atop rocky cores. However, this was so far inconsistent with the presence of migrated, water-rich planets.

We found in our simulations that we recover the radius valley at the observed position if we include supercritical steam atmospheres in combination with photoevaporation of mixed H/He and water. The exclusion of the lower-density supercritical phase of water was a shortcoming of previous models and is key for the population of observed, hot exoplanets.

Three effects are at play: First, Type I migration moves a population of initially ice-rich sub-Neptunes to the inner system. Second, the - at these temperatures - supercritical water contained in the migrated planets separates this population from the rocky planets in radius or density space. Lastly, photoevaporation of both water and H/He further de-populates the valley.

Demographics & Architectures
Planetary Population Synthesis, Radius Valley, Theory

13:30 - 14:30 Parallel Talks 5

1. GAPS2: Unveiling the young exoplanet population history by joining transit and radial velocity techniques

Parallel Talk675Ilaria Carleo; IAC

AalmarktzaalTue 13:30 - 14:30

The “GAPS” (Global Architecture of Planetary Systems) project gathers a large part of the Italian community working on exoplanets. One of our aims, with the Young Objects sub-program of GAPS2 (GAPS-YO), is the search for young exoplanets, since they are the key targets to study the early evolution of planetary systems affected by the high-energy irradiation of the young stellar host, and understand the origin of their observed diversity.

GAPS-YO searches for young planets by surveying members in young and intermediate age associations, and performs a HARPS-N radial velocity follow-up of young transiting candidates, mainly provided by the NASA-TESS satellite. We present both the single planetary systems and the overall view of the young sample characterised so far. Our survey allows us a preliminary assessment on the impact of stellar age and photo-evaporation on the mass/radius relationship and on the apparent higher frequency of hot Jupiters around very young stars.

RV and transits
Young exoplanets

2. Rotational axes and precession rates of exoplanets

Parallel Talk737Dmytro Orikhovskyi; Astronomical Institute of the Slovak Academy of Sciences

AalmarktzaalTue 13:30 - 14:30

The number of hot Jupiters on misaligned orbits around hot and rapidly rotating stars has been steadily increasing. Fast rotation of exoplanet host stars causes their flattening and in misaligned systems leads to precession of the orbital planes and rotational axes of planets. The orbital plane precession results in transit duration variations due to the changes in the orbital plane inclination angle.While the Doppler tomography of transiting exoplanets is the most reliable way to determine projected spin-orbit misalignment, gravity darkening in fast rotators can produce asymmetric transit light curves that can constrain the misalignment. This is possible, however, only in high-precision satellite data.The first results of the search for misaligned and precessing systems using the TESS satellite light curves are presented. Preliminary orbital and planetary parameters for the most promising systems are given.

RV and transits
Precession

3. Probing the early evolution of planetary systems

Parallel Talk1178Edward Gillen; Queen Mary University of London

AalmarktzaalTue 13:30 - 14:30

Stars in young associations, open clusters and co-moving groups can be precisely dated, which make them promising targets for exoplanet searches seeking to probe the early evolution of planetary systems. Detecting young transiting planets has been historically difficult, however, because young stars display significant variability, which masks the planetary transits. Our new search algorithm, Wiggle, simultaneously models the stellar variability using Gaussian process regression as it searches for transits, which increases its sensitivity to small planets. I will present a dedicated search for young planets in TESS 2-min data, which has so far detected the youngest transiting planet candidate to date, a new 100 Myr old planetary system comprising two sub-Neptunes, a handful of promising new candidates, and the serendipitous detection of new complex rotators and young eclipsing binaries. I will conclude with an outlook towards furthering our understanding of how planetary systems evolve with TESS.

RV and transits
Young transiting planets

4. Transit Ephemerides and Timing Variations from Kepler and K2 to TESS

Parallel Talk1166Suzanne Aigrain; University of Oxford

AalmarktzaalTue 13:30 - 14:30

We present a catalogue of refined ephemerides, transit parameters and timing residuals for 121 planets in 117 systems that were discovered in Kepler or K2 data and observed again by TESS. We analysed every such system where individual transits were detectable in TESS data and were actually observed. The additional baseline allowed us to improve the precision on the linear ephemerides for all most all systems, by a factor ranging from 2 to 10 depending on the system parameters. We confirm previously-known TTVs in 19 systems, and find new evidence for either periodic timing residuals or non-linear trends in the times of 24 other systems. Of particular interest are Kepler-522b, which shows TTVs of 20 minutes in amplitude, and K2-348, which hosts two transiting Neptune-sized planets for which TESS data shows long-term second order trends.

RV and transits
Kepler, TESS

1. Characterizing the Distribution of Water Vapor and Pebble Drift Efficiency in Disks with JWST MIRI

Parallel Talk1075Carlos Munoz-Romero; Harvard University

BreezaalTue 13:30 - 14:30

Prior to JWST, Spitzer revealed an anti-correlation between mid-IR water vapor luminosity and millimeter dust disk radius. This provided evidence for water enrichment in compact disks, which may experience highly efficient icy pebble drift compared to larger, more structured disks. Yet due to the limited capabilities of Spitzer, the degree of water enrichment has been mainly studied qualitatively. We now present a detailed analysis of JWST MIRI spectra of six nearby protoplanetary disks part of the JDISC survey, with dust radii spanning 10 to 200 au. We model the water emission accounting for multiple temperature components, as well as radial temperature and density gradients for the first time. These models allow us to estimate the rate of pebble drift and water mass that has sublimated near the snow line. In turn, we can begin to place constraints on the properties of planets that can form in the innermost disk regions.

Formation and evolution
Chemistry, Disks, Pebble, Water

2. The Dynamical Evolution of Exoplanet Systems Over Billions of Years

Parallel Talk83Stephen Schmidt; Johns Hopkins University

BreezaalTue 13:30 - 14:30

Exoplanet systems are expected to evolve with time as they age. This expected evolution of exoplanet systems over billion-year timescales has been extremely difficult to observe. We have shown that Galactic kinematics can provide accurate and precise age inferences for exoplanet populations and thereby uniquely constrain models of planet formation and evolution. Our latest work recently revealed at the population level that (1) plausibly mean-motion resonant multiple-planet systems are among the youngest exoplanet systems with ages τ ~ 1 Gyr and (2) systems with an ultra-short-period (USP) planet are among the oldest exoplanet systems with τ ~ 8 Gyr. The former observation implies that convergent disk-driven Type I migration often leaves newly formed planetary systems in mean-motion resonances. The latter observation suggests that USP planets tidally migrate from their locations at the end of the planet formation process to their observed locations over several billion years.

Formation and evolution
Exoplanet system ages, Resonant systems, Ultrashortperiod (USP) planets

3. Formation of rocky super-Earths from a ring of planetesimals

Parallel Talk368Alessandro Morbidelli; Collège de France

BreezaalTue 13:30 - 14:30

The formation of super-Earths, the most abundant planets in the Galaxy, remains elusive. These planets appear to be predominantly rocky, and frequently occur in multiples in a peas-in-the-pod pattern. Here we advance a theoretical picture for rocky planet formation that satisfies the aforementioned constraints: building upon recent work, which has demonstrated that planetesimals can form rapidly at discrete locations in the disk, we propose that super-Earths originate inside rings of silicate-rich planetesimals at approximately ~1 au. Within the context of this picture, we show that planets grow primarily through pairwise collisions among rocky planetesimals until they achieve terminal masses that are regulated by isolation and orbital migration. We quantify our model with numerical simulations and demonstrate that our synthetic planetary systems bear a close resemblance to compact, multi-resonant progenitors of the observed population of short-period extrasolar planets.

Formation and evolution
origin, planet dynamics

4. AGE-PRO: The ALMA survey of Gas Evolution in PROtoplanetary disks

Parallel Talk543Paola Pinilla; University College London

BreezaalTue 13:30 - 14:30

Robust measurements of the gas content in the birth-site of planets remain elusive, even though the gas reservoir regulates the first steps of planet formation and determines the final planet mass and their migration. In this talk, I will present the results of the ALMA Large Program AGE-PRO, which aims to trace the evolution of gas density throughout the lifetime of protoplanetary disks by quantifying for the first time the gas masses and sizes of 30 disks across the whole range of disk lifetimes (0.1-10 Myr). I will present the initial statistics of gas disk mass evolution in our sample, and compare with theories of disk evolution. Our dust continuum observations favour the presence of weak dust traps (still unresolved in our observations), such as the ones originated from cold Neptune-type planets; making AGE-PRO sample an excellent laboratory to understand giant-planet formation throughout the evolution of protoplanetary disks

Formation and evolution
Disk evolution

1. High dispersion optical phase curves of ultra-hot Jupiters with SHINE ON.

Parallel Talk691Lorenzo Pino; INAF - Osservatorio Astrofisico di Arcetri

Grote ZaalTue 13:30 - 14:30

Ultra-hot Jupiters (UHJs; Teq ≥ 2500 K) are the hottest gaseous giants known. They emerged as ideal laboratories to test (1) theories of atmospheric structure and climate under extreme irradiation, and (2) planet formation theories, due to the unique presence of gaseous refractory elements (e.g. Fe).Theoretical studies show that they should be close to chemical equilibrium, offering a direct link between thermal structure and composition. In addition, their climate should differ, for example due to the emergence of atmospheric drag (due to ionization). Yet, observational support is still sparse.The SHINE ON program aims to fill this gap of knowledge through optical high dispersion phase curve observations of about 15 UHJs, obtained with some of the best instruments for this purpose (VLT ESPRESSO and Gemini-N MAROON-X). I will present the first results from this program, and some of the challenges and opportunities in interpreting this kind of data.

Atmospheres
Exoplanet atmospheres, High dispersion spectroscopy

2. The Roasting Marshmallows Campaign: High Spectral Resolution Characterization of Exoplanet Atmospheres with IGRINS

Parallel Talk567Michael Line; Arizona State University

Grote ZaalTue 13:30 - 14:30

Ground based high resolution time-series spectroscopy of transiting planets can reveal insights into planetary atmospheric composition, chemistry, and dynamics. Here we present results from nearly 200 hrs of ongoing programs with the Immersion GRating INfrared Spectrometer (IGRINS) on Gemini South aimed at measuring the compositions and thermal structures of over a dozen transiting exoplanets. We will present current results of this survey including the detections of H2O, CO, and OH, abundance constraints, and thermal structure information across a range of planetary temperatures (~1400-3000 K). The overall goal of this effort is to demonstrate the reliability and the potential of ground based high-resolution spectroscopy to rigorously inform our understanding of the nature of exoplanet atmospheres, identify the role of ground based spectroscopic characterization in the era of JWST, and to create a pathway for atmospheric characterization with the next generation of giant ground based giant segmented mirror telescopes.

Atmospheres

3. Strongly varying water absorption in the ultra-hot Jupiter WASP-121b at high spectral resolution

Parallel Talk1298Joost Wardenier; Université de Montréal

Grote ZaalTue 13:30 - 14:30

The atmospheres of ultra-hot Jupiters (UHJs) are vastly non-uniform in terms of chemistry, temperature, dynamics, and cloud cover, which makes their observed spectra challenging to interpret. Resolving their transmission spectra as a function of time provides crucial insights into the “3D nature” of these planets.

We present the first ever time-resolved water and CO absorption signals of an UHJ, based on three transits of WASP-121b observed with GEMINI-S/IGRINS at high spectral resolution. While CO absorption remains equally strong during the transit, the water signal displays significant variation, suggesting water dissociation or cloud formation on one of the limbs of the planet. Also, both molecules display different Doppler shifts, which we demonstrate are due to their unique spatial distribution across the atmosphere. We compare our observations to a suite of global-circulation models and their corresponding 3D spectra, to paint an accurate, multi-dimensional picture of the limb region of WASP-121b.

Atmospheres
3D atmospheric characterization, Global circulation models, Ultrahot Jupiters

4. High resolution spectroscopy of ultra-hot Jupiters at optical wavelengths: Inversions, cold traps and limb asymmetries

Parallel Talk328Jens Hoeijmakers; Lund University

Grote ZaalTue 13:30 - 14:30

Ultra-hot Jupiters (UHJ) orbit hot early type stars in short periods and are heated to extreme temperatures far over 2,000 K on their day-sides. All but the most strongly bound molecules are dissociated and many atoms may be significantly ionised. The dominant sources of line opacity are due to metals and some molecules including metal oxides. Much of these absorb efficiently at short wavelengths, causing strong thermal inversions. These inversions affect the atmospheric structure, chemistry, as well as global circulation of gas and heat. Excitingly, these thermal inversions can be observed effectively using high-resolution spectroscopy of the day-side, where a multitude of metals exhibit line emission. Together with transmission spectroscopy that senses the day-to-night terminator, we can use these observations to constrain the chemical and thermal structures of UHJ atmospheres in three dimensions. We have analysed observations of a collection of UHJ's, and find tantalising commonalities and differences between them.

Atmospheres
Atmospheric chemistry, Emission spectroscopy, Highresolution, Ultrahot Jupiters

14:40 - 15:40 Parallel Talks 6

1. The PLATO Mission – An Overview

Parallel Talk88Heike Rauer; DLR

AalmarktzaalTue 14:40 - 15:40

PLATO is ESA’s M3 mission and designed to detect and characterize extrasolar planets by photometrically monitoring a large number of stars. PLATO will detect small planets around bright stars, including terrestrial planets in the habitable zone of solar-like stars. With the complement of radial velocity observation from ground, planets will be characterized for their radius, mass, and age with high accuracy. PLATO will provide us with a large-scale catalogue of well-characterized small planets up to intermediate orbital periods, relevant for a meaningful comparison to planet formation theories and to better understand planet evolution. In parallel, PLATO will study (host) stars using asteroseismology, allowing us to determine the stellar properties with high accuracy, substantially enhancing our knowledge of stellar structure and evolution. PLATO´s open Complementary Science program will allow for a number of additional science cases, based on proposals from the community. We will provide an overview of the PLATO mission.

Future missions/instrumentation
astroseimology, habitability, space mission, transit method

2. The Earth 2.0 (ET) Space Mission

Parallel Talk571Shude Mao; Tsinghua University

AalmarktzaalTue 14:40 - 15:40

The Earth 2.0 (ET) space mission has entered its phase B study in China, with the goal to address key questions: how frequently habitable Earth-like planets orbit solar-type stars (Earth 2.0s), how terrestrial planets form and evolve? and what is the origin of free-floating planets? ET consists of six 28 cm diameter wide field transit telescope systems and one 35 cm diameter microlensing telescope. ET will monitor ~1.2M FGKM dwarfs in the Kepler and its neighboring fields continuously for four years as well as over 30M I< 20.5 stars in the Galactic bulge direction. ET is expected to identify ~17 Earth 2.0s, about 5000 Earth-sized terrestrial planets and over 30,000 new planets, as well as to measure masses of over 300 microlensing planets. ET will be operated at the Earth-Sun L2 orbit with a designed lifetime longer than 4 years. Updates on this mission study will be provided.

Future missions/instrumentation
Earth 2.0, Habitabletransit

3. Ariel: science and community engagement programs

Parallel Talk1549Giovanna Tinetti; UCL

AalmarktzaalTue 14:40 - 15:40

Ariel was adopted as the fourth medium-class mission in ESA's Cosmic Vision program to be launched in 2029. During its 4+ year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The Ariel payload is developed by a consortium of 16 ESA countries and contributions from NASA, JAXA and CSA. This presentation provides an overall summary of the science and instrument design for Ariel and presents the many activities that the Ariel team have planned to engage the science community at large and the public prior to launch. These include the Ariel Dry-Run program and citizen-science programs such as ExoClock and the Ariel Data Challenges.

Future missions/instrumentation
Chemistry, Exoatmospheres

4. TESS: Current Status and Extended Mission Planning

Parallel Talk1654George Ricker; MIT Kavli Institute for Astrophysics and Space Research

AalmarktzaalTue 14:40 - 15:40

The Transiting Exoplanet Survey Satellite (TESS) is NASA’s ongoing mission for discovering exoplanets, and for exploring the time-variable sky. TESS’s scientific output has grown rapidly over the past 6 years, resulting in >7000 planet candidates and ~2000 scientific publications— including 576 papers in 2023 alone.TESS’s 2nd Extended Mission (EM2:2023-2025) will bring its sky coverage to >95%. EM2 has also adopted the TESS Image CAlibrator (TICA) data product, making fully-calibrated 200s full-frame images publicly available within ~2-3 days of downlink.For TESS’s 3rd Extended Mission (EM3:2025-2028), we are planning to build on accomplishments of the past six years by: 1) providing prompt ( ⪅1 day) public image data to observers for selected temporal events; 2) conducting long duration surveys of the TESS-JWST-Roman continuous viewing zones near the ecliptic poles, enabling the discovery of more long period systems and also potentially coordinating with (or complementing) the PLATO baseline survey.

Other

1. Wet or dry? Pebble sublimation in hot atmospheres predicts a compositional dichotomy for planets

Parallel Talk665Chris Ormel; Department of Astronomy, Tsinghua University; Yu Wang; Department of Astronomy, Tsinghua University

BreezaalTue 14:40 - 15:40

Planets that form in disks come with hot envelopes. Pebble-sized particles that get accreted through this hot envelope, will likely lose their volatile components by sublimation. What happens to this vapor -- will it stay in the envelope or return to the disk through recycling flows -- determines the final composition of the planet. Focusing on the water content of super-Earths, we have conducted multifluid hydrodynamical simulations that, for the first time, accounted for phase change processes (here: sublimation and condensation of H2O ice). We observe a bifurcation in our results: (i) A recycling-dominated atmosphere with steady and low vapor, dry content; or (ii) ineffective recycling and an increasingly vapor-dominated, wet, atmosphere. Our results predict a dichotomy of rocky planets and "water worlds" as recently proposed for M-dwarfs.

Formation and evolution
Atmosphere, Hydrodynamics, Sublimation

2. ALMA’s View of Planet-Forming and Photoevaporating Disks in the Orion Nebula Cluster

Parallel Talk1264Nicholas Ballering; University of Virginia

BreezaalTue 14:40 - 15:40

I will present multi-band high-resolution ALMA observations of over 100 protoplanetary disks in the Orion Nebula Cluster (ONC). The ONC offers the clearest view of disks in a rich cluster—the typical environment for star formation in the Galaxy and the type of environment in which the solar system formed. These observations measure disk masses and sizes, key properties in determining what types of planets can form. I will present a statistical comparison with disks in nearby low-mass star-forming regions to assess the impact of cluster environments on planet formation. I will also highlight ALMA images of a dozen proplyds—disks in the process of being photoevaporated by the cluster’s harsh radiation field. These reveal a compact disk surrounded by free-free emission from ionized gas flowing off the disk and yield an independent measurement of the disk mass-loss rate due to external photoevaporation.

Formation and evolution

3. Sublimating ices feeding forming giant planets

Parallel Talk391Alice Booth; Center for Astrophysics | Harvard & Smithsonian

BreezaalTue 14:40 - 15:40

New planetary systems are made from dust, gas and ice in the rotating disks around young stars. We can therefore only unravel exoplanet composition demographics through our knowledge of protoplanetary disk chemistry. For this, high-sensitivity observations of these disks with the Atacama Large Millimeter Array (ALMA) are essential. ALMA can trace the composition of the gas available to be accreted by planets and in this talk, I will present recent molecular line observations from a survey of disks around young intermediate (~2 solar) mass stars. By targeting different molecules we can trace the elemental abundances in the disk's gas (e.g, C/O), determine the availability of volatile sulphur, and, measure the complex organic reservoir. Additionally, we look also for direct detections of planets via planetary heating and/or shocks. Since gas giant planets are more likely to form in this class of disks these observations probe the chemical environment of giant-planet formation.

Formation and evolution
planet formationplanet compositionastrochemistry, protoplanetary disks

4. `Dracula’s Chivito’: The largest protoplanetary disk in the sky

Parallel Talk1040Kristina Monsch; Center for Astrophysics | Harvard & Smithsonian

BreezaalTue 14:40 - 15:40

We present the first resolved images of the giant edge-on protoplanetary disk named Dracula's Chivito (DraChi), in optical scattered light with Pan-STARRS, and millimeter thermal emission with the SMA. DraChi is hosted around a massive Herbig Ae/Be-type star located in an isolated region of the Cepheus star forming region, being in direct vicinity of a hot X-ray bubble that is hypothesized to have been created by a massive supernova explosion. Depending on the adopted distance estimate, DraChi's dust and gas radii span enormous physical scales, ranging from 540-1100 au in scattered light, and 900-1840 au in the 1.3 mm dust emission, placing it among the largest protoplanetary disks ever reported physically, and the largest in angular extent yet known. As such, DraChi may be the precursor of extremely massive planetary systems hosting multiple giant planets, such as HR 8799.

Formation and evolution
Herbig Ae/Be stars

1. The peculiar case of high C/O and high metallicity atmosphere of tau Bootis b

Parallel Talk1257Vatsal Panwar; University of Warwick

Grote ZaalTue 14:40 - 15:40

Atmospheric compositions of exoplanets hold clues to the formation pathways sculpting the exoplanet population. Recent ground-based high-resolution spectroscopy of the hot Jupiter tau Bootis b from different instruments have resulted in a tension in atmospheric abundance of water. This has significant implications for the planet’s formation history because non-detection of water implies high atmospheric C/O and metallicity, which is difficult to explain using standard core accretion. To investigate this, we revisit the K band CRIRES observations of the planet's dayside and reanalyse them using the latest methods for correcting systematics and atmospheric retrieval. We confirm the detection of CO and constrain its abundance, but do not detect water, confirming the peculiar composition of the planet’s atmosphere. We also obtain a tantalizing tentative detection of methane, which is unexpected for the planet's equilibrium temperature. We will discuss the potential sources of the methane detection, including contribution from the planet's night side.

Atmospheres
3D atmospheric structure, high resolution crosscorrelation spectroscopy

2. Investigating the Day-side Atmosphere of an Ultra Hot Jupiter using IRD/Subaru

Parallel Talk645Stevanus Kristianto Nugroho; Astrobiology Center

Grote ZaalTue 14:40 - 15:40

We performed high-resolution emission spectroscopy probing the day-side atmosphere of an ultra-hot Jupiter, WASP-33b, using the InfraRed Doppler instrument (IRD) on the Subaru telescope. As a result, we confirmed our previous detection of OH emission at >9 sigma after the secondary eclipse. We also confirmed previous detections of Fe I, Si I, and Ti I, and found evidence of Mg I and Mn I emission after combining all data sets, which, if also confirmed, add more chemical species that have been detected on the day-side of an exoplanet. Through several tests, the weak/non-detection of OH before the eclipse is likely due to astrophysical phenomena indicating that the spatial distribution of each chemical species is different and that we are probing different parts of this 3D atmosphere. This highlights the 3-D properties of an exoplanet that needs to be taken into account when characterising its atmosphere.

Atmospheres
emission, exoplanet atmosphere, highresolution spectroscopy, ultra hot jupiter

3. Double Delight: CRIRES+ Exploration of Luhman 16's Binary Atmospheres

Parallel Talk247Sam de Regt; Leiden Observatory, Leiden University

Grote ZaalTue 14:40 - 15:40

The chemical and isotopic content of exoplanet- and brown dwarf atmospheres can provide clues about their formation histories. The dynamics and chemistry of these atmospheres can be constrained with high-resolution spectroscopy. In this talk, I will present an analysis of the nearby brown dwarf binary Luhman 16. As part of the ESO SupJup Survey, both components were observed in J- and K-band with the upgraded CRIRES+ spectrograph. The high spectral resolution and high signal-to-noise allow for a unique insight into the composition and ongoing atmospheric processes of sub-stellar objects at the L-T transition. I will discuss line shape peculiarities as well as the detection and interpretation of rare molecules and isotopologues.

Atmospheres
Atmospheres, Chemistry

4. Phase-resolved emission spectroscopy of WASP-18b probed by CRIRES+

Parallel Talk410Fei Yan; University of Science and Technology of China

Grote ZaalTue 14:40 - 15:40

Phase-resolved high-resolution spectroscopy is a powerful technique for studying the atmospheric circulation of exoplanets. We observed the dayside thermal emission spectrum of WASP-18b using the newly upgraded CRIRES+ spectrograph. The observation covered a large range of orbital phases from 0.25 to 0.75, allowing us to perform phase-resolved analysis based on the detected CO emission lines. By employing a full retrieval code, we were able to obtain the velocity and line profile of the CO lines at different orbital phases. These phase-resolved velocity and line profiles provide direct information on the rotation rate and atmospheric circulation pattern, which can be further compared with predictions from GCM models.

Atmospheres
highresolution spectroscopy, thermal emisison spectroscopy, ultrahot Jupiter

16:10 - 16:55 Parallel Talks 7

1. Understanding the formation of small planets by searching for their cold giant siblings

Parallel Talk923Aldo Stefano Bonomo; INAF - Osservatorio Astrofisico di Torino

AalmarktzaalTue 16:10 - 16:55

The exoplanet population with relatively short orbital periods around solar-type stars is dominated by small planets (SPs), i.e. super-Earths and sub-Neptunes. These planets are, however, missing in our Solar System, and the reason for that is unknown. By studying the impact of cold Jupiters (CJs) on the formation and/or migration of SPs, several theoretical works have predicted either an anti-correlation or a weak or strong correlation between CJs and SPs, thus reaching somehow contradictory results. Here we report on the search for and occurrence rate of CJs in the largest considered sample of Kepler, K2 and TESS transiting systems with high-precision radial velocities. We found no evidence of previous claims of an excess of CJs in small-planet systems, and we show how our occurrence rate may provide fundamental clues on both the formation of short-period SPs and their absence in our Solar System.

Demographics & Architectures
planet formation and evolution, statistical methods

2. KGPS I: A Decade of Kepler Planet Host Radial Velocities from W. M. Keck Observatory

Parallel Talk1103Lauren Weiss; University of Notre Dame

AalmarktzaalTue 16:10 - 16:55

To investigate the relationship between close-in small, and distant giant planets, we conducted the Kepler Giant Planet Survey (KGPS). Using W. M. Keck Observatory HIRES, we spent a decade collecting 2844 RVs of 63 sun-like stars that host 157 transiting planets. We had no prior knowledge of which systems would contain giant planets beyond 1 AU, making this survey unbiased with respect to previously detected Jovians. We announce 27 RV-detected companions to 20 stars from our sample: 13 Jovians, 8 sub-Saturns, 3 stellar-mass companions, and 3 ambiguous trends, along with updated masses and densities of 84 transiting planets. The KGPS project leverages some of the longest-running, most data-rich RVs of the NASA Kepler systems yet, and will address whether giant planets help or hinder the growth of sub-Neptune sized and terrestrial planets. Future papers will examine the relationship between small, transiting planets and their long-period companions.

Demographics & Architectures
transits

3. RV homogeneous analysis of an HARPS sample of M-Dwarfs : Planetary occurrence statistics

Parallel Talk1243Lucile Mignon; Université de Genève

AalmarktzaalTue 16:10 - 16:55

After two decades in operation, HARPS stands out as one of the most precise, stable, and consequently prolific planet-searcher spectrographs. Despite its non-optimization for low-mass stars due to their limited brightness in the optical range, we monitored over 200 M dwarfs with HARPS since 2003. This presentation outlines a systematic and homogeneous analysis of the 200 radial velocity time series, from the extraction of velocity values using a template-matching method optimized for M dwarfs to the development of tools to establish a new planetary occurrence statistic.Our results robustly confirm the prevalence of low-mass planets at short periods around these stars. Furthermore, we propose new rates for massive planets at large separations, made accessible by the exceptional longevity of HARPS. Additionally, working on sub-samples based on stellar mass, we investigate the dependence of the planetary population on the central mass and highlighted notable discrepancies.

Demographics & Architectures
Mdwarfs, Occurrence, population, Radial velocity

1. Observations of warm Jupiter orbital architectures as a test of giant planet migration theories

Parallel Talk635Elyar Sedaghati; European Southern Observatory

BreezaalTue 16:10 - 16:55

Existence of close-in giants poses a difficult challenge to our understanding of planet formation. Such theories typically invoke migration beyond the snow line, through interactions with either the protoplanetary disk or an outer, eccentric companion. One way to test such theories is to observe their orbital architectures; namely eccentricity and obliquity relative to stellar spin axis, latter of which is measured through Rossiter-McLaughlin effect during primary transit.

I present the results of an on-going survey aiming to determine such architectures for a sample of ∼10 warm-Jupiters, using ESPRESSO/VLT. Our sample includes only those systems where orbits are long enough (P≥10days) for stellar tidal effects to be ineffective in reprocessing primordial orbital configuration, that pose an observational challenge due to rarity and duration of their transits.

These systems present architectures from aligned and eccentric to mis-aligned and circular, pointing to inadequacy of current formation theories and the need to revise them.

Formation and evolution
Migration theories, Orbital obliquity, RossiterMcLaughlin

2. Host-star properties of hot, warm and cold Jupiters from Gaia DR3: clues to formation

Parallel Talk1165B Bihan; Tata Institute of Fundamental Research Mumbai

BreezaalTue 16:10 - 16:55

Exo-Jupiters exhibit diverse orbital properties, suggesting distinct formation and dynamic histories. Here we present how these orbital properties are linked to their host-star properties, particularly metallicity and age. We obtain metallicities and velocity dispersion for host-stars of hot, warm, and cold Jupiters from Gaia DR3. Average ages of these groups are computed using velocity dispersion-age relation. We find that host-stars of hot Jupiters are relatively metal-rich and young compared to the host-stars of cold Jupiters in nearly circular orbits. Host-stars of cold Jupiters in high-eccentric orbits show metallicities similar to that of the hosts of hot Jupiters, but are older, on average. The similarity in host-star metallicity between the two supports tidal migration of cold Jupiters in high-eccentric orbits as the potential origin of hot Jupiters. However, the difference in age suggests destruction of older hot Jupiters by stellar tides, thus placing a constraint on the stellar tidal quality factor.

Formation and evolution
Exoplanet migration, Gaia, Hot Jupiters, Tidal interaction

3. The Overlooked Carbon-Rich Exoplanets

Parallel Talk441Edwin Bergin; University of Michigan

BreezaalTue 16:10 - 16:55

I present a new model for planet composition focusing on carbon supply. For many planetary systems, the water iceline within the planet-forming disk is a focal point, representing the boundary between where water-rich and water-poor planets form. We posit that the soot line, the location inside of which solid-state organics are irreversibly destroyed, is also a key location. Based on this model we predict a population of planets will form on short-period orbits with significant organic inventories but low amounts of water. As a result, the mantle of such a planet could be rich in reduced carbon but have low water content. Outgassing would naturally yield the ingredients for haze production, which is widely observed in sub-Neptune-sized exoplanets. Although this type of planet has no solar system counterpart, it should be common. We will present simulations of the planetary atmospheric compositions and discuss the potential implications for the mass-radius relation.

Formation and evolution
Carbon, Formation

1. JWST + VLT reveal a giant planet atmosphere enriched in volatiles relative to refractories.

Parallel Talk1578Stefan Pelletier; Université de Montréal

Grote ZaalTue 16:10 - 16:55

Planets are formed from three components: gas, ice, and rock. And yet, amazingly, there are currently no giant planets (including those in our Solar System) for which the abundances of the main ice-forming and rock-forming elements have been directly spectroscopically measured. With temperatures where all atmospheric constituents are vaporised, the daysides of ultra-hot Jupiters offer an unprecedented opportunity to simultaneously measure the ice and rock content of giant planets. Here we present an comprehensive view of the ultra-hot Jupiter WASP-121b in thermal emission from JWST/NIRISS, VLT/CRIRES+, and VLT/ESPRESSO. By combining JWST with ground-based high-resolution observations, we obtain unprecedented constraints on the elemental composition, temperature structure, and dynamics of WASP-121b’s atmosphere. Interestingly, we find an enrichment similar to Jupiter for volatiles but no equivalent enrichment for refractories, indicating that WASP-121b may have formed in a volatile-rich environment with a higher ice-to-rock ratio than is typically assumed for giant planets.

JWST Results
Atmospheres, Formation, Highresolution

2. Exometeorology: A Multi-Pronged Approach with JWST

Parallel Talk907Johanna Vos; Trinity College Dublin

Grote ZaalTue 16:10 - 16:55

We are entering the era of direct exoplanet characterisation studies. Based on the handful of directly-imaged exoplanets studied to date, it is clear that interpretation of these discoveries hinges on a thorough understanding of their complex atmospheric phenomena. With unprecedented sensitivity, wavelength range and photometric stability, the advent of JWST enables a paradigm shift in our understanding of extrasolar worlds. I will present results across three JWST GO programs (#3486, #3496, #3548) that will provide an unprecedented, multi-dimensional view of extrasolar atmospheres. Program #3486 will reveal equator-to-pole atmospheric differences beyond our solar system, Program #3548 will enable longitudinally-resolved characterisation of the cloud and atmospheric properties in an isolated, planetary-mass world, and Program #3496 will enable the first vertically-resolved wind speed measurements in any extrasolar atmosphere. Together, these programs will provide crucial and transformational insight into the spatial and temporal behaviour of key atmospheric processes in giant extrasolar worlds.

JWST Results
Atmospheres, Atmospheric Retrievals, JWST

3. A simultaneous reflected-light and thermal emission spectroscopic phase curve of an exo-Neptune

Parallel Talk1403Louis-Philippe Coulombe; Université de Montréal

Grote ZaalTue 16:10 - 16:55

The exoplanet LTT 9779b is the most irradiated Neptune-sized planet known to date, making it the ideal laboratory to study the chemistry and dynamics of an ultra-hot exoplanet atmosphere in the lower mass regime, which is still unexplored. We present the JWST NIRISS/SOSS spectroscopic phase curve and phase-resolved emission spectra of the ultra-hot Neptune LTT 9779b. The observations simultaneously cover the reflected light and thermal emission-dominated regimes of the planetary spectrum at all phases. The retrieved albedos and temperature-pressure profiles across orbital phases are well explained by a global circulation and cloud pattern involving highly reflecting silicate clouds being transported from the cold nightside towards the dayside by an equatorial jet, where they then evaporate near the hottest longitudes of the planet before recondensing towards the eastern terminator. The transport of these clouds towards the dayside could explain the survival of LTT 9779b in the hot Neptune desert.

JWST Results
Spectroscopic phase curve

17:05 - 17:50 Parallel Talks 8

1. Low-Mass M Dwarfs Lack Jupiter Analogs

Parallel Talk1352Emily Pass; Center for Astrophysics | Harvard & Smithsonian

AalmarktzaalTue 17:05 - 17:50

For the terrestrial planets of our solar system, Jupiter was an important influence: it sculpted the dynamical environment in which these worlds formed, affecting the delivery of volatiles, the terrestrial refractory budget, and potentially, Earth's overall habitability. We investigated the occurrence rate of Jupiter-like planets around inactive, low-mass (0.1-0.3M⊙) M dwarfs—which host the only terrestrial exoplanets amenable to atmospheric study with JWST—by monitoring a volume-complete sample of 200 such stars over six years, collecting four high-resolution spectra per star. We did not detect any Jupiter-mass planets at Jupiter-like instellations, yielding a 95%-confidence upper limit of 1.7% on the occurrence rate of Jupiter analogs. In contrast, surveys of Sun-like stars have found that their giant planets are most common just beyond the snow line, at these Jupiter-like instellations. Our results indicate that solar-system-like architectures are rare around low-mass M dwarfs, with implications for the evolution and habitability of their terrestrial worlds.

Demographics & Architectures
M dwarfs, surveys

2. A multi-technique approach in the study of the frequency of hierarchical systems across spectral types

Parallel Talk186Matteo Pinamonti; INAF - Osservatorio Astrofisico di Torino

AalmarktzaalTue 17:05 - 17:50

Despite being the most abundant classes of known exoplanets, super-Earths and sub-Neptunes are absent in our Solar System, and the reason for this is still uncertain, with some models suggesting that cold Jupiters prevent the formation of inner planets.In this framework, we take advantage of high-resolution echelle spectroscopy from HARPS-N, and high-precision Gaia astrometry to study planetary systems across different spectral types. We present the high-cadence and high-precision Radial Velocity (RV) monitoring of hosts to long-period giants with well-measured orbits, in search for inner planets, over different spectral types from M to G. We also show how the combination of RV measurements and high-precision Gaia astrometry can greatly expand our knowledge of the long-period planets orbiting the observed systems. From these analyses, we highlight a very different behavior between earlier and later stars, which suggests an opposite influence of cold Jupiters in the formation of inner planetary systems.

Demographics & Architectures
Astrometry, Demographics, Radial velocity

3. A homogenous analysis of small planet masses

Parallel Talk510Hannah Osborne; UCL Mullard Space Science Laboratory

AalmarktzaalTue 17:05 - 17:50

Our current view of the mass-radius relationship of small exoplanets, and therefore our understanding of exoplanet compositions and demographics, is not giving the full picture. Planet masses found through precision radial velocity observations are inconsistent; the offsets between different instruments, the data reduction pipelines, and the method used to account for stellar activity varies between studies. The effect of these inconsistencies can cause a significant difference in terms of the extracted planet mass. To combat these issues we have completed a homogenous analysis of 45 systems hosting small exoplanets, using publicly available HARPS data. We asses and compare the impact of different data extraction techniques and modelling choices on the subsequently measured planet masses.

I will present the results of this new work, providing a new view of the small exoplanet mass-radius relation, which will impact our understanding of small planet compositions.

Demographics & Architectures

1. Where Are the Water Worlds? Identifying the Exo-Water-Worlds Using Genesis Population Synthesis Models

Parallel Talk1406Aritra Chakrabarty; Data Observatory and Universidad Adolfo Ibanez

BreezaalTue 17:05 - 17:50

Migration models of planet formation suggest the presence of water-ice-rich cores in several super-Earths and sub-Neptunes, referred to as water worlds. While direct measurements of the mass and radius of some observed planets hint at this composition, confirming it remains challenging based solely on density. To address this, we introduce the Genesis Population Synthesis models, combining planet formation models from the Genesis database with models of atmospheric accretion, evolution, and escape via photo-evapopration and impacts. Comparing predictions with Kepler- and TESS-planet statistics in mass-radius-period space, we identify occurrence trends for potential water/ice-rich planets. Our findings suggest that water worlds are likely prevalent at orbital periods > 10 days, slightly longer than current targets for spectroscopic observations. This insight aids in optimizing target selection for future observatories like JWST and GMT, offering opportunities to test the water-world hypothesis.

Demographics & Architectures
Kepler planet distributions, Migration model

2. Sub-Neptune Formation: The View From Resonant Planets

Parallel Talk820Nick Choksi; UC Berkeley

BreezaalTue 17:05 - 17:50

Where there is one close-in sub-Neptune, there is usually at least another. We examine the 3:2 and 2:1 resonant populations and show that their distribution of orbital period ratios conclusively decides between assembly in a gas-rich disk (e.g., by pebble accretion) or in a gas-poor disk (e.g., by giant impacts). We also show that resonances established during the final doublings in mass are stable, contrary to earlier claims. Just as important as the period ratios are the strong transit timing variations (TTVs) observed near resonance. Besides an amplitude and a period, a sinusoidal TTV has a phase, often overlooked. We explain how TTV phases act like a kind of integration constant, encoding information about initial conditions or planetary environment. We use TTV phases to scope out distant companions to close-in planets, and to argue that resonant planets may have eccentricities an order of magnitude larger than previously supposed.

Demographics & Architectures
In situ formation, Multiplanet systems, Resonances, Transit timing variations

3. First measurements of abundance in exocomets.

Parallel Talk545Théo Vrignaud; Institut d'Astrophysique de Paris

BreezaalTue 17:05 - 17:50

Extrasolar comets – or exocomets – are icy bodies placed on elliptical orbits which sublimate when they reach their periastron, producing extensive clouds of dust and gas – the so-called "cometary tails". The most famous star known to harbor such objects is Beta Pictoris, a young (20 Myr) A-type star, for which transiting comets are detected daily using absorption spectroscopy. However, despite more than 35 years of observations, still very little information on the composition of these objects is known. Here, I will present a new analysis of archival HST/STIS data, which led to the first measurement of the abundance of several metallic species – Si, Fe, Ni, Mn - within the tails of Beta Pictoris exocomets, and to the estimate of their physical properties. These results are of crucial importance to better understand the history of these objects and the main mechanisms at work within their gaseous tails.

Other
Beta Pictoris, Exocomets

1. The Transmission Spectrum of the Super-Puff Exoplanet Kepler-51b as Observed by JWST

Parallel Talk32Peter Gao; Earth and Planets Laboratory, Carnegie Institution for Science

Grote ZaalTue 17:05 - 17:50

One of the strangest discoveries of the Kepler mission is a rare class of low mass, large radius, and low-density planets that has been nicknamed "Super Puffs". These objects challenge formation and evolution theories due to their inferred large gas mass fractions, which could be an order of magnitude higher than those of the smaller and much more numerous - but similar mass - sub-Neptunes. Here we reveal the 1-5 micron transmission spectrum of Kepler-51b as observed by JWST, with the aim of looking for signatures of hazes, rings, and atmospheric molecules. We find clear signatures of molecular absorption in our preliminary analysis, as well as tentative hints of hazes and/or rings. The molecular absorption will allow us to constrain the atmospheric metallicity and C/O of Kepler-51b, finally shedding light on the origins and evolution of this enigmatic class of exoplanets.Friday, September 22nd

JWST Results
SuperPuff

2. Revisiting GJ 436b’s Atmosphere with Panchromatic JWST Emission Spectroscopy

Parallel Talk696Sagnick Mukherjee; University of California, Santa Cruz

Grote ZaalTue 17:05 - 17:50

GJ 436b is the archetype warm Neptune exoplanet, with an equilibrium temperature of ~ 700 K. The planet’s thermal emission spectrum has been previously observed via secondary eclipse campaigns with Spitzer and HST. The atmosphere has long been interpreted to be extremely metal-rich, out of chemical equilibrium, and potentially tidally heated. Here we present the first panchromatic emission spectrum of GJ 436b observed with JWST NIRCAM (F332W & F444W grism) and MIRI (LRS) instruments from 2.4 to 11.9 um. The JWST emission spectrum appears significantly different from that implied by Spitzer photometry. We use this panchromatic emission spectrum to put constraints on the temperature-pressure profile, atmospheric metallicity, C/O ratio, and cloud structure using a retrieval framework. We also employ 1D photochemical modeling to interpret the chemical composition of the planet’s atmosphere from the emission spectrum and shed light on the interior heat and strength of vertical mixing in its atmosphere.

Atmospheres
Eclipse Spectroscopy, Warm Neptunes

3. JWST reveals abundant methane and depleted carbon dioxide on the temperate sub-Neptune LP719-18c

Parallel Talk1355Pierre-Alexis Roy; Trottier Institute for Research on Exoplanets, Université de Montréal

Grote ZaalTue 17:05 - 17:50

With three transiting planets spanning both ends of the radius valley, the LP791-18 system is the ideal laboratory to study the atmospheric evolution of sub-Neptune exoplanets. Here, we present the detection of methane in the atmosphere of the temperate sub-Neptune LP791-18c via a JWST NIRSpec/PRISM transit observation. The transmission spectrum of LP791-18c is dominated by strong methane absorption at 2.3 and 3.3 μm, and by the presence of opaque hazes at short wavelengths. While our retrieved methane abundance is consistent with that recently measured on K2-18b, LP791-18c’s spectrum, in stark contrast, shows no sign of carbon dioxide absorption, allowing us to derive stringent constraints on its depletion. Our discovery thus points towards LP791-18c hosting a deep reducing atmosphere, and is a powerful example of the diversity of sub-Neptune envelopes, as even analog planets in density and temperature are observed with vastly different compositions.

JWST Results
Atmospheres, Methane detection, SubNeptunes

Wednesday 19 June 2024

09:30 - 10:00 Plenary Talks 5

1. The First JWST Spectrum of a White Dwarf Exoplanet

Plenary Talk1405Ryan MacDonald; University of Michigan

Grote ZaalWed 09:30 - 10:00

One day, the Sun will die. While the outer giant planets in our solar system will likely survive the death of the Sun, their long-term state is a matter of considerable uncertainty [1]. Recently, several intact giant exoplanets have been discovered orbiting white dwarfs [e.g., 2,3], which can provide a glimpse into the eventual fate of our solar system.I will present the first JWST observations of a giant planet orbiting a white dwarf: WD 1856b. WD 1856b orbits its host white dwarf at 0.02 au, causing considerable debate about how the planet survived the red giant phase and migrated inwards after the main-sequence [e.g., 4,5]. Our transmission spectrum of WD 1856b accomplishes the first atmospheric detection of a white dwarf planet. I will discuss the implications of our results for the evolutionary history and atmospheric chemistry of a post-main-sequence exoplanet.

JWST Results
JWST

2. Empirical Constraints on Tidal Dissipation in Exoplanet Host Stars

Plenary Talk1079Sarah Millholland; Massachusetts Institute of Technology

Grote ZaalWed 09:30 - 10:00

The orbits of short-period exoplanets are sculpted by tidal dissipation. However, the mechanism and efficiency of these tidal interactions are poorly constrained. We present robust constraints on the tidal quality factors of short-period exoplanetary host stars through the usage of a novel empirical technique. The method is based on analyzing structures in the population-level distribution of decay times, defined as the time remaining before a planet spirals into its host star due to stellar tides. Using simple synthetic planet population simulations and analytic theory, we show that there exists a steady-state portion of the decay time distribution with an approximately power-law form. This steady-state feature is clearly evident in the decay time distribution of the observed short-period planet population. We use this to constrain both the magnitude and frequency dependence of the stellar quality factor and show that the stellar Q’ must decrease sharply with planetary orbital period.

Demographics & Architectures
Hot Jupiters, Orbital decay, Tides

11:00 - 11:30 Plenary Talks 6

1. The atmospheres and migration of three planets with a compact system with JWST/NIRSpec

Plenary Talk1545Matthew J. Hooton; University of Cambridge

Grote ZaalWed 11:00 - 11:30

Laplacian resonant chains — where astronomical bodies are in mean motion resonance with two or more other bodies — are rare phenomena observed in systems such as the TRAPPIST-1 exoplanets and the Galilean moons of Jupiter. Laplacian chains are an important tool to study the history of planetary systems occupying this configuration, as the fragility of the chain significantly constrains the possible pathways through which the planets can form and evolve. Observations with TESS, CHEOPS, NGTS and SPECULOOS of the nearby K-dwarf TOI-178 revealed a compact system of six transiting super-Earths and mini-Neptunes: five of which form a chain of Laplacian resonance. ESPRESSO RVs revealed uncommon planet-to-planet density variations. In this talk, I will present our analysis of recently-acquired JWST/NIRSpec transmission spectra of three planets in the TOI-178 system, which reveal their atmospheric compositions and test whether they formed in situ or migrated to their current separations.

JWST Results
JWST, TOI178

2. Jupiter Mass Binary Objects - JuMBOs

Plenary Talk1622Samuel Pearson; European Space Agency

Grote ZaalWed 11:00 - 11:30

In recent observations of the Trapezium Cluster with the JWST, we have discovered and characterised a sample of 540 planetary-mass candidates with masses down to 0.6 Jupiter masses. In an unexpected twist we find that 9% of these planetary-mass objects are in wide binaries. The binary fraction of stars and brown dwarfs is well known to decrease monotonically with decreasing mass such that the binary fraction for the planetary-mass regime is expected to approach zero. The existence of substantial population of Jupiter Mass Binary Objects (JuMBOs) raises serious questions of our understanding of both star and planet formation. In this talk I will present the discovery of these JuMBOs, the 540 free-floating planetray-mass candidates, and discuss the implications for our understanding of planet formation.

JWST Results
JWST, Multiplicity, Planet formation

Thursday 20 June 2024

08:30 - 17:50 Poster round 3

1 visit is better than none, but are 2 visits better than one? “Hot Rock” LHS-1478b at 15um with JWST/MIRI.

Poster1017Prune Camille August; DTU Space

Poster AreaThu 08:30 - 17:50

Are exoplanets orbiting M dwarf capable of retaining atmospheres? And if so, which ones? This is the pressing question the Hot Rocks Survey (JWST GO 3730, PI: Hannah Diamond-Lowe) aims to address by observing the secondary eclipses of nine terrestrial exoplanets spanning various planet and host star properties.

LHS-1478b was observed in emission with JWST/MIRI at 15um on two occasions to get the appropriate S/N to confirm or reject the presence of an atmosphere. Unfortunately, the second observation is plagued by systematics, making it difficult to identify the signal of the occultation. While work is still in progress to treat this data, we present the results of visit 1, where the eclipse was detected, measured, and interpreted in context with atmospheric & surface models using HELIOS.

JWST Results
eclipse photometry

A Bayesian model for RV extraction

Poster959André M. Silva; Instituto de Astrofísica e Ciências do Espaço

Poster AreaThu 08:30 - 17:50

The level of precision needed to detect Earth-like planets orbiting other suns motivates new developments in both instrumentation (e.g. ESPRESSO) and data analysis. The s-BART (Silva+2022) semi-Bayesian, template-matching, framework was built around the assumption that an achromatic RV-shift describes the differences between stellar spectra and a stellar model. However, as the stellar model is built from observations of the star, it leads to a mixture of information between it and the data with which it is compared to (observations), which isn't fully compatible with a Bayesian framework

To overcome such limitation, a move towards a fully probabilistic stellar model is required, capable of simultaneously extracting RVs and correcting telluric features. In this talk, we present a new methodology that leverages Gaussian Processes to generate a model of the stellar spectra whilst estimating the RV separation between observations. The model and preliminary, promising, results will be presented.

RV and transits
RV extraction, Spectral modelling

A comprehensive homogeneous investigation of orbital ephemeris and transmission spectrum of WASP-19 b.

Poster1006Anitha Raj Rajkumar; Universidad de Atacama

Poster AreaThu 08:30 - 17:50

Exoplanets with ultra-short periods such as WASP-19b might experience orbital decay due to the tidal dissipation effect with the host star. With the availability of long-term high-precision photometric and spectroscopic data including 28 unpublished transits from the Danish telescope, allows verification of the orbital ephemeris of the WASP-19b and place limits on the modified tidal quality factor Q’*. The same data allows for a detailed study of the atmospheric properties of WASP-19b, via transmission photometry and spectroscopy.WASP-19A is an active host star with its surface littered with starspots, which if not correctly modeled, systematics are introduced into the transit depth and transit timing measurements. Therefore, to perform a full and complete orbital ephemeris study of WASP-19b requires the modeling of detected starspots. Using the transit-starspot model, PRISM we perform the most complete, detailed, homogeneous analysis of all available data to estimate Q’* and study the atmospheric properties of WASP-19b.

Star-planet interactions
Exoplanet atmospheres, Ultrahot Jupiters

A DREAM study: spectroscopic search for sodium around the hot Neptune desert

Poster1208Sara Tavella; University of Geneva

Poster AreaThu 08:30 - 17:50

Close-in exoplanets exhibit a desert of hot Neptunes. Atmospheric photoevaporation driven by intense XUV stellar irradiation strongly contributes to shaping the desert, leaving a direct imprint in planets at its edges. The DREAM project focuses on those border worlds to study the desert’s origin, investigating their orbital architectures and atmospheric composition. Here, we exploited high-resolution transmission spectroscopy to search for atmospheric sodium in 10 targets – including the well-known super-Neptune WASP-166b for reference. Sodium traces the XUV-induced heating of planetary thermospheres, thus their expansion and escape. Correlating its presence with systems’ properties helps constrain the role of stellar irradiation in close-in planets evolution. After applying state-of-the-art spectral corrections, we derived from the out-of-transit stellar spectrum a proxy for the local planet-occulted sodium lines. Using this proxy and the derived orbital architectures, we fitted measured absorption spectra with realistic EVE simulations that include Rossiter-McLaughlin distortions to accurately constrain planetary sodium abundances.

Atmospheres
hot Neptune desert, sodiumDREAM

A multi-wavelength view of M-dwarfs activity with SOPHIE and SPIRou: characterizing low-mass planets

Poster1230Pia Cortes-Zuleta; University of St Andrews

Poster AreaThu 08:30 - 17:50

Stellar activity remains one of the main limitations to discovering low-mass planets. In radial velocity (RV) searches it induces extra RV jitter, hampering the detection of semi-amplitudes below ~1 m/s. Moreover, this signal is usually quasi-periodic which can lead to false-positive exoplanet detection. However, one way to address this challenge is to observe at multiple wavelengths as the activity-induced RV variability is chromatic. In this talk, I will introduce the synergy project between SOPHIE at OHP and SPIRou at CFHT, two high-precision spectrographs in the optical and near-infrared, respectively. I will show its M-dwarf sample, main goals, and results. In particular, I will present our recent analysis of the chromaticity of the stellar activity signal in two M-dwarfs with different activity levels, one very active[1] and another moderately active[2], and the detection of a planetary system around the primary component of a close-in binary system[3].

RV and transits
lowmass planets, Mdwarfs, stellar activity

A new, adaptive time step, hybrid symplectic, N-body integration scheme for planetary systems.

Poster1173Simon Grimm; ETH Zurich

Poster AreaThu 08:30 - 17:50

N-body integrators are an essential tool to study planetary systems in many aspects. A very common integration method is the hybrid symplectic integrator which conserves the energy of the system over large integration times, and can handle close encounters between different bodies accurately. A major problem with this integrator is that the time step must be set to a fixed value. That can bring a significant performance penalty. Here, we present a new method, which allows to use adaptive and individual time steps, but still keeps the symplectic properties of the integrated systems, and therefore allows a large speedup in the computing time.

Formation and evolution
Nbody, Simulation

Accounting for the impact of wavelength-correlated noise on transmission spectra

Poster1209Mark Fortune; Trinity College Dublin

Poster AreaThu 08:30 - 17:50

The impact of time-correlated noise on transmission spectra has long been understood [1] and is often accounted for using Gaussian processes (GPs) [2]. We present a new optimisation for GPs which can efficiently account for both time and wavelength-correlated noise [3]. We fit all spectroscopic light curves simultaneously, retrieving the full covariance matrix of the transmission spectrum. Testing on simulated data has demonstrated that our method can fully account for wavelength-correlated noise while standard approaches may significantly underestimate uncertainties in features such as a scattering slope and overestimate uncertainties in sharp absorption peaks. We present how wavelength-correlated systematics affect transmission spectra for ground-based observations from VLT/FORS2 as well as for space-based observations from HST and JWST. These results suggest previous ground-based haze detections may be unreliable and that this systematics treatment is important for combining multiple transit observations including observations of small planets with JWST.

Atmospheres

Airy worlds or barren rocks? On the survivability of secondary atmospheres around the TRAPPIST-1 planets.

Poster1172Gwenaël Van Looveren; University of Vienna

Poster AreaThu 08:30 - 17:50

JWST is currently at the forefront in the search for exoplanet atmospheres. However, the observation of atmospheres of Earth-like planets pushes the limits of the instruments, often requiring multiple observations to be combined. Their interpretation requires complementary theoretical studies to test plausible atmospheric models. We aim to determine the atmospheric survivability of rocky planets around late M-type dwarfs by modelling the upper atmosphere of the TRAPPIST-1 planets' response to incoming stellar extreme ultraviolet and X-ray (XUV) radiation. This is done using a self-consistent thermo-chemical code to create a grid of models simulating possible atmospheres. Specifically we study the atmospheric mass loss due to Jeans escape induced by XUV radiation. Our models indicate that even Jeans escape is catastrophically large for these N2 or CO2 dominated atmospheres over evolutionary timescales, which has important observational implications.

Star-planet interactions
atmospheric loss, TRAPPIST1

An Earth-sized Exoplanet Orbiting an M2 Star

Poster1272Francis Zong Lang; Center for Space and Habitability, University of Bern

Poster AreaThu 08:30 - 17:50

TOI4616, a system with a planet of size 1.22R⊕ and an orbital period of 1.554

days has been detected by the NASA TESS mission and later characterized

with the SAINT-EX telescope. We study this system to characterise

the properties of the planet and its host star and use transit photometry to con-

strain critical parameters of the planet such as its mass and orbital dynamics.

By employing a series of aperture and PSF photometry methods to determine

the crowding metric and the flux fraction to compute an accurate transit depth

obtained from the SAINT-EX light curves and constrain the necessary plane-

tary parameters.

The validation of the orbital period of 1.554 days reinforces our understand-

ing of rocky exoplanets around low-mass stars. We expect TOI4616 to be a

rocky exoplanet with the possibility of hosting an atmosphere.

RV and transits
Earthsized planet, parameter characerization, Transit depth, Ultracool star

Architects of the Cosmos: JWST Reveals Protoplanets as the Origin of Disk Structures

Poster1051Gabriele Cugno; University of Michigan

Poster AreaThu 08:30 - 17:50

Observations of circumstellar disks have showcased a stunning diversity in substructures possibly linked to the formation of protoplanets. Despite significant efforts, ground-based near-infrared imaging identified only two protoplanets in the iconic PDS70 system and a few candidates. Thanks to its unparalleled sensitivity in the 4-11 micron range, JWST is probing lower mass, colder and redder scenarios than previously possible.Several programs targeted protoplanetary disks with both NIRCam and MIRI. In this talk, we will present the exciting results from several of these programs, including the detection of protoplanet candidates associated with scattered light spirals and kinematic perturbations of the disk gas. In addition, we will present the measurement of accretion line fluxes at Pa-alpha and Br-alpha for the PDS70 planets, providing a more comprehensive picture of their ongoing accretion processes. These findings carry significant implications for our understanding of planet formation and evolution, particularly in discerning between initial planetary entropy.

JWST Results
Planet formation, protoplanets detection

Ariel - The ESA M4 Space Mission to Focus on the Nature Of Exoplanets

Poster1221Theresa Luftinger ; ESA/ESTEC

Poster AreaThu 08:30 - 17:50

The goal of the ESA M4 mission Ariel is to investigate the atmospheres of planets orbiting distant stars in order to address the fundamental questions on how planetary systems form and evolve and to investigate the diversity of exoplanets and their atmospheres. Ariel will observe up to 1000 exoplanets - building on findings from space missions like PLATO, JWST, TESS, and CHEOPS - in a wide variety of environments, in the visible and the infrared. The analysis of Ariel spectra and photometry will allow to extract the chemical fingerprints of atmospheric gases and condensates, including elemental composition and planetary weather for the most favourable targets. The Ariel mission has been developed by a consortium of more than 60 institutes from 15 ESA member state countries, including UK, France, Italy, Poland, Spain, the Netherlands, Belgium, Austria, Denmark, Ireland, Hungary, Sweden, Czech Republic, Germany, Portugal, with additional contributions from NASA & CSA.

Future missions/instrumentation
Ariel, Atmospheres, Space Missions

Assembly of Exoplanetary Atmospheres: Towards a New Framework for Data Interpretation and Life Detection

Poster1084Estelle Janin; Arizona State University

Poster AreaThu 08:30 - 17:50

Assembly Theory introduces a new way to quantify the complexity of a system based on the minimum number of steps it takes to combinatorically assemble it from a pool of building blocks. It captures signatures of selection and evolution and has been used to accurately characterize the biogenicity of molecular systems. We apply it to the chemistry of planetary atmospheres and consider graphical representations of a large diversity of gaseous envelopes, informed by atmospheric and radiative transfer models (e.g., atmos, GGChem, TauREx). Within a Bayesian framework consistent with the observation of partial data, we reconstruct the chemical Assembly Space of exoplanetary atmospheres and output the shortest Pathway characterising their formation and evolution history in combinatorial time. This framework provides a new theoretical ground for exoplanet data interpretation and allows to test specific hypotheses related to the presence of a biosphere and how the complexity it generates translates into the atmosphere.

Habitability
Assembly Theory, Atmospheres, Combinatorial Chemistry, Life Detection

Blueshifted Fe I emission in dayside of WASP-76b detected with ESPRESSO

Poster1156Christophe Lovis; Observatoire Astronomique de l'Université de Genève

Poster AreaThu 08:30 - 17:50

The extremely hot atmospheres of ultra hot Jupiters (UHJs) are excellent targets for atmospheric characterisation studies using ground-based high-resolution emission spectroscopy. We present the first high-resolution optical emission spectra for the UHJ WASP-76b. This planet was observed on four epochs with ESPRESSO (VLT), before and after its eclipse, when the dayside is in view. We searched for signatures of FeI and FeII in the dayside, which can confirm the existence of a thermal inversion layer. Furthermore, we investigate how the atmospheric profile impacts the detection. We apply cross-correlation function (CCF) techniques and detect a blueshifted (-4.6km/s) FeI signature on the dayside of WASP-76b, at 6.7-sigma (co-added CCFs) and 14.1-sigma (Kp-vsys plot). FeII was not detected, possibly due to the smaller amount of spectral lines available in the optical range. We propose that material moving radially outward from the hotspot on the dayside could explain our FeI detection.

Atmospheres
ESPRESSO, Highresolution Emission Spectroscopy, Ultra Hot Jupiters, WASP76b

CALM thy stars: a new spectral-based stellar variability modeling method for RV searches

Poster977Zoë L. de Beurs; Massachusetts Institute of Technology

Poster AreaThu 08:30 - 17:50

Exoplanet detection with precise radial velocity (RV) observations is currently limited by spurious RV signals introduced by stellar activity (i.e. faculae, starspots). Here we show that our modeling method, CCF Activity Linear Model (CALM), can significantly improve RV measurements by separating the activity signals from real center-of-mass RV shifts. We have tested our method on observations from both EXPRES and HARPS-N. These techniques can successfully predict and remove stellar activity and reduce the RMS by about 40% for the most active stars (Zhao, L.L. et al. 2022). We also successfully applied our methods to measure the mass of K2-167, a planet which was first found using the transit method in 2015 (de Beurs et al. submitted). This enables searches of stars spanning the HR diagram to help measure planet masses and may eventually help detect habitable-zone Earth-mass exoplanets.

RV and transits
activity

Can 1D radiative equilibrium models of faculae be used for calculating contamination of transmission spectra?

Poster1185Veronika Witzke; Max Planck Institute for Solar System Research

Poster AreaThu 08:30 - 17:50

Transmission spectra are contaminated by stellar magnetic activity. To disentangle the planetary and stellar contributions to transmission spectra and reliably characterise planetary atmospheres, it is essential to realistically model stellar magnetic features. Current retrieval algorithms used in transmission spectroscopy rely on intensity contrasts of magnetic features from one-dimensional (1D) models. However, magnetic features, especially faculae, are not captured by such simplified models. Using 3D radiative magnetohydrodynamics simulations representing quiet stellar regions and facular regions, we show that 1D models dramatically fail to reproduce the wavelength dependence of the facular contrast, taking a G2V star as an example. Our result has far-reaching consequences for exoplanet characterisation using transmission spectroscopy.

Atmospheres
Exoplanet surface composition, Faculae

Changing disc compositions via internal photoevaporation

Poster963Julia Lienert; Max Planck Institute for Astronomy

Poster AreaThu 08:30 - 17:50

We use a disc model that includes pebble growth, drift, evaporation and condensation as well as a chemical partitioning model to study how internal photoevaporation affects the evolution and composition of protoplanetary discs. This then constrains the formation environment of exoplanets and their atmospheric composition.

We show that internal photoevaporation plays a major role in the (chemical) evolution of protoplanetary discs. As it opens a gap, inward drifting pebbles are stopped and volatile-rich gas is carried away by photoevaporative winds. Consequently, the C/O ratio in the inner disc remains low. Additionally, we find a high water content there because the water vapour and ice go through a constant cycle of evaporation and recondensation.

We conclude that it is very important to take internal photoevaporation into account when simulating the evolution of protoplanetary discs as it changes their composition drastically, which in turn has a large impact on forming exoplanets.

Formation and evolution
internal photoevaporation, protoplanetary discs

Characterizing Giant Exoplanet Atmospheres with the Nancy Grace Roman Space Telescope Coronagraph Instrument

Poster1133Zarah Brown; University of Arizona

Poster AreaThu 08:30 - 17:50

The Nancy Grace Roman Space Telescope Coronagraph Instrument is set to be the most powerful coronagraph to date. By effectively mitigating host star glare, this technology demonstration will allow for the direct imaging of cool jovians in reflected light and self-luminous hot young jovians, paving the way for future missions targeting terrestrial-sized planets. Spectral analysis of exoplanets imaged with the Roman Coronagraph Instrument (RCI) could be used to identify atmospheric components, including gases, hazes and clouds, to help characterize these planets’ atmospheres. With limited telescope time and capabilities, meticulous planning for observations with RCI is imperative. We are engaged in constructing predictive models for existing target candidates. These models will serve to optimize target selection, supporting the effective use of RCI and ultimately advancing our understanding of jovian exoplanet atmospheres.

Future missions/instrumentation
Atmospheres

Clouds and Hazes in GJ 1214b’s Metal Rich Atmosphere

Poster1080Isaac Malsky; The University of Michigan

Poster AreaThu 08:30 - 17:50

GJ 1214b is the archetypal sub-Neptune. A recent JWST spectroscopic phase curve has shown that it has a reflective metal-rich atmosphere. Previous transmission spectra indicated thick aerosols in GJ 1214b’s atmosphere, and this recent work hypothesized that those aerosols are a highly reflective haze. Using a 3D General Circulation Model with both photochemical hazes and condensate clouds, we characterize how different aerosol types affect the atmospheric structure of GJ 1214b and manifest in observables. We find that a scenario with both clouds and hazes is most consistent with the JWST phase curve. Reflective mineral clouds are needed to explain the large Bond albedo, and hazes and a super-solar metallicity are needed to account for the several hundred Kelvin day-night temperature difference consistent with the phase curve. Our models offer unique insight into planets within this regime, where clouds and hazes can shape the 3-D atmospheric structure in concert.

Atmospheres
3D Models, Atmosphere, Clouds

Comparing transit spectroscopy pipelines at the catalogue level: evidence for systematic differences

Poster1495Luke Booth; Cardiff University

Poster AreaThu 08:30 - 17:50

In the burgeoning era of the James Webb Space Telescope (JWST) and the upcoming ARIEL mission, ensuring consistent data interpretation in exoplanetary science is critical. This study pioneers in contrasting pipeline results at a catalog level, addressing a fundamental challenge in the field. Using observations from HST-WFC3, we systematically compare the outputs of three distinct pipelines: Iraclis, EXCALIBUR, and CASCADe. Our analysis reveals notable differences in the spectra and compositional trends of exoplanets, highlighting the inconsistencies in data interpretation despite identical starting data and planetary parameters. These variations, not accounted for in standard uncertainties, suggest potential biases in information retrieval, posing risks to the accuracy and reliability of exoplanetary research. Our findings highlight the urgency to address these discrepancies, underlining the importance of understanding pipeline-induced biases to avoid skewed perceptions of exoplanets as a collective class.

Future missions/instrumentation
HST, JWST

Connecting the Atmosphere, Interior, and Outflow of the Dying Ultrahot Jupiter HAT-P-67 b

Poster950Zafar Rustamkulov; Johns Hopkins University

Poster AreaThu 08:30 - 17:50

Ultrahot Jupiters are a diverse population of worlds uniquely poised for precision metal budgeting with both atomic and molecular transitions. We present the most precise NUV-optical (0.2-0.9 micron) space-based transmission spectrum of an ultrahot Jupiter. HAT-P-67 b is a planet rapidly losing mass in the harsh light of its evolved F star. Our new HST-UVIS observation resolves a plethora of excited atomic absorption features that trace a massive outflow, corroborating recent findings. We also detect prominent SiO absorption, which defies chemical equilibrium expectations, and serves as a new thermometer for the planet's hot interior. We present the chemical inventory, an updated RV mass, and joint structure models of the planet's interior, atmosphere, and exosphere, shedding new light on the late-stage evolution of hot gas giants. We show resulting constraints of the planet's accreted rock-to-ice ratio to speculate about its origins, and compare it to the population of ultrahot Jupiters.

Atmospheres
HST, Ultrahot Jupiters

Convective mixing during gas giant evolution

Poster1284Jesse Polman; Space Research and Planetary Sciences, Physics Institute, University of Bern,

Poster AreaThu 08:30 - 17:50

The atmospheres of gas giants provide insights into their formation and evolution. It is often assumed that these planets consist solely of a solid core and a fully mixed envelope. This simplification makes it possible to extent atmospheric properties, such as the metallicity and C/O ratio, to the rest of the planet. Recent analysis of Jupiter's composition hints at the existence of a dilute core. It is essential to understand the conditions under which dilute cores can form and survive over the lifetime of a planet, so that we can accurately relate atmospheric properties to bulk properties for exoplanets. We present the results of our effort to model convective mixing throughout the evolution of gas giants. We discuss necessary conditions for retaining a dilute core, as well as processes that still need to be considered to improve our understanding.

Formation and evolution
Convection, Dilute core

Critical external and internal factors for plate tectonics

Poster1278Oliver Henke-Seemann; Freie Universität Berlin

Poster AreaThu 08:30 - 17:50

Convective mantle flow in terrestrial planets is governed by a temperature- and pressure-dependent rheology. This results in a stagnant-lid regime observed on most terrestrial planets. Plastic deformation can lead to breaking of the strong upper lithosphere, which resembles plate tectonics on Earth. With Venus being the most Earth-like planet we can closely study, identifying the factors that led to the apparent absence of plate tectonics on Venus is vital in understanding the evolution of rocky exoplanets.

In order to determine the likelihood of plate tectonics, we investigate the influence of internal and external planetary factors, mainly surface temperature and yield stress. We employ a viscoplastic rheology in a 2D-spherical annulus geometry. The models are evaluated by computing common diagnostic values used to recognize plate-like surface deformation. The goal of this study is to identify key planetary factors for the occurrence or absence of plate tectonics.

Interiors
Mantle Convection Modelling, Surface Temperature

Decoding atmospheric compositional gradient of close-in gas-giant archetypes

Poster957Hinna Shivkumar; University of Amsterdam

Poster AreaThu 08:30 - 17:50

Close-in gas giants, with their significant day-night contrast, are excellent laboratories for understanding atmospheric climate and chemistry. Due to a large temperature gradient in their dayside vs. nightside, we expect atmospheres of close-in giants to exhibit a strong atmospheric chemical gradient; we selected the best targets to study such gradients with HST and JWST. We apply the phase-curve extraction method based on common-mode correction, which removes observational systematics and uses the stellar spectrum in eclipse to retrieve the planetary spectrum, and characterize atmospheric compositional variation as a function of longitude. Additionally, our method allows for the measurement of the nightside temperature of tidally locked planets, from which we estimate the energy budget of the planet. We also demonstrate the strength of our method, extending it to long-period planets and their partial phase curve observations, for interpreting chemical gradients in the atmospheres of exoplanets, especially in the JWST era.

Atmospheres
HotJupiters, Phase Curves

Deeper understanding of rocky planet atmospheres through Atmospheric Retrievals of super-Earth L98-59d using JWST

Poster1233Agnibha Banerjee; The Open University

Poster AreaThu 08:30 - 17:50

L 98-59d is a super-Earth orbiting an M-type star in the “venus zone”[1], and has one of the highest TSM[2] values among such planets. We perform retrievals on the transmission spectrum of L 98-59d obtained using NIRSpec G395H during a single transit, from GTO 1224.The wavelength range of this spectrum allows us to potentially detect the presence of several atmospheric species, such as H2O, CO2, CO[3] and even SO2, which could serve as an indicator of volcanism on rocky planets[4]. Furt