ESA's MADRID-Area Exoplanet Science Meeting (MAESM) 2024

Programme

Abstracts

Update on PLATO status ( J. Miguel Mas Hesse,  CAB (CSIC-INTA))

I will summarize the present development status of the PLATO mission and the statistics of the analysis performed on the first long pointing field to be observed.

Exoplanetary research: in the path to the Habitable World Observatory ( Ana Ines Gomez de Castro,  Joint Center for Ultraviolet Astronomy/JCUVA - Universidad Complutense de Madrid)

This would be just a short talk about the HWO project status seeking for feedback from the European Community as ESA representative in HWO.

The KOBE experiment: first results ( Olga Balsalobre Ruza,  CAB (CSIC-INTA))

Late K-dwarf stars are promising hosts for habitable planets. Their low activity levels reduce the threat of violent events like stellar flares, helping to create a favorable environment for the potential development of life. Additionally, their habitable zones are at distances close enough to allow the detection of rocky planets, but also beyond the range of strong tidal forces thus preserving daily cycles on the planet's surface. For these characteristics, K dwarfs provide an optimal balance between detectability and habitability as compared to G and M dwarfs. The KOBE experiment is a radial velocity survey of 50 late-K dwarfs designed to detect planets within their so far under-explored habitable zones. In this talk, we will present the first planetary system discovered by KOBE through a radial velocity monitoring with the CARMENES spectrograph.

Status of the Gaia mission and its exoplanet science opportunities ( Johannes Sahlmann,  ESA - ESAC)

I will present a status update of the Gaia mission, discuss a few recent exoplanet-related science results from Gaia, and present an outlook towards the fourth Gaia data release which offers new opportunities for exoplanet research.

CHEXANET: A Novel Approach to Fast-Tracking Disequilibrium Chemistry Calculations for Exoplanets Using Neural Networks ( Antónia Vojtekova,  University College London (UCL))

In the rapidly evolving field of exoplanetary science with missions like JWST and Ariel, there is a pressing need for fast and accurate simulations of disequilibrium chemistry in exoplanet atmospheres. Methods which assume chemical equilibrium simplify calculations but fail to capture the more complex chemical dynamics observed in actual exoplanets. Accurate estimations require complex kinetic codes that are time-intensive due to the need to solve ordinary differential equations. Given an extensive parameter space that needs to be explored to calculate forward models, kinetic codes will become a significant bottleneck, especially when used to match observations or in retrieval processes. We introduce CHEXANET, a novel U-Net-based neural network architecture designed to efficiently simulate disequilibrium chemistry in exoplanetary atmospheres. By utilising the thermochemical equilibrium state of a hot-Jupiter's atmosphere as an initial condition, which computes in seconds, alongside a set of initial parameters such as the C/O ratio, the network effectively learns to predict the atmosphere in disequilibrium. It significantly enhances computational efficiency, reducing the prediction time for atmospheric disequilibrium states to just one second per atmosphere on a standard personal computer—over a hundred times faster than traditional kinetic models like FRECKLL.

Your opportunities with ESA's CHEOPS: updates after nearly five years in orbit ( Maximilian Guenther,  ESA - ESTEC)

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 launched on 19 December 2019, and has since then completed its 3.5-year-long Nominal Mission and is in the middle of its first Extended Mission, providing the community with even more opportunities to get involved and apply for observing time. Chat with us to discuss your ideas and submit your proposals!

Mapping the exo-Neptunian landscape: A ridge between the desert and savanna ( Amadeo Castro-González,  CAB (CSIC-INTA))

Atmospheric and dynamical processes are thought to play a major role in shaping the distribution of close-in exoplanets. A striking feature of such distribution is the Neptunian desert, a dearth of Neptunes on the shortest-period orbits. In this talk, I will review our recent work, where we aimed to define the boundaries of the Neptunian desert and study its transition into the savanna, a moderately populated region at larger orbital distances. We identified an overdensity of planets separating the Neptunian desert from the savanna (3.2 days ⪅ Porb ⪅ 5.7 days) that stands out at a 4.7σ level above the desert and at a 3.5σ level above the savanna, which we propose to call the Neptunian ridge. The period range of the ridge matches that of the well-known hot Jupiter pileup (≈3-5 days), which suggests that similar evolutionary processes might act on both populations. We find that the occurrence fraction between the pileup and warm Jupiters (Δpileup/warm = 5.3 ± 1.1) is about twice that between the Neptunian ridge and savanna (Δridge/savanna = 2.7 ± 0.5). This indicates either that the processes that drive or maintain planets in the overdensity are more efficient for Jupiters, or that the processes that drive or maintain planets in the warm region are more efficient for Neptunes. Our revised landscape supports a previous hypothesis that a fraction of Neptunes were brought to the edge of the desert (i.e. the newly identified ridge) through high-eccentricity tidal migration (HEM) late in their life, surviving the evaporation that eroded Neptunes having arrived earlier in the desert. The ridge thus appears as a true physical feature illustrating the interplay between photoevaporation and HEM, providing further evidence of their role in shaping the distribution of close-in Neptunes.

Data-Intensive pipeline for robust exoplanetary analysis: Application to the long-period exoplanet TOI-4409 b ( Patricio Reller,  University College London (UCL))

We present a data-intensive pipeline in development to improve the reliability and robustness of exoplanetary science, with an initial focus on lightcurves and radial velocity data analysis. By integrating and comparing different modelling methods, the pipeline refines parameter posterior distributions by addressing the assumptions and noise treatments unique to each approach. Its modular design allows specific algorithms and components to be compared in isolation, building on existing pipelines to achieve more precise results. As a proof of concept, we apply this framework to the long-period exoplanet candidate TOI-4409 b, observed across 14 transits by multiple instruments (TESS, ASTEP, CHAT, and OMES). Our combined analysis confirms its presence around the host star and refines its physical characteristics as initially derived from TESS data. We welcome feedback on desired features to optimise the pipeline's usability for diverse research applications.

Gas disks limit the innermost planetary orbits ( Ignacio Mendigutía,  CAB (CSIC-INTA))

The orbits of hot Jupiters could be explained from the innermost properties of the protoplanetary disks where they born. In particular, the hot region where dust sublimates, and the magnetosphere where gas is truncated, have both been proposed as effective disk barriers limiting the smallest orbits that planets can have. However, observational tests aiming to disentangle between the two previous barriers are difficult because the location of the inner dust and gas disks roughly coincide for low-mass stars (0.5 - 1.5 Msun). This talk summarises our recent work in Mendigutía et al. (2024, A&A, 686, L1), where we compared the orbits of hot Jupiters with the positions of the inner dust and gas disks. Intermediate-mass stellar hosts (1.5 - 3 Msun) were included in the analysis because the dust and gas barriers are spatially separated for these stars. Our results support that the inner gas -and not the dust- disk limits the innermost planetary orbits. A major implication is that hot Jupiters should be more probably swallowed by massive host stars (> 3 Msun), where magnetospheres are absent.

The quest for the He I 10830 triplet in exoplanets ( Jorge Sanz-Forcada,  CAB (CSIC-INTA))

Exoplanet atmospheres photoevaporate because of XUV stellar irradiation. Evaporation signs are detected mainly through the H Lyman-alpha line, or more recently in the He I 10830 line (actually a triplet). Despite of early efforts back in 2000 to find this line in transiting exoplanets, it was not until 2018 that the line was finally detected. The stellar high energy irradiation also plays a role in this line formation, but no direct observation of most of the XUV spectral range is possible in stars other than the Sun. We present an update of the X-exoplanet database, and improved scaling laws to calculate the XUV flux, that take into account the stellar activity level. Despite of the efforts to find a clear relation between the He I 10830 detections in exoplanet atmospheres, and the stellar XUV irradiation, this relation remained elusive so far. We report a new parametrization that empirically confirms the relation between stellar XUV irradiation and the formation of the He I 10830 triplet in exoplanet atmospheres.

Constraining atmospheric escape in exoplanets from the ground with SPIRou ( Adrien Masson,  CAB (CSIC-INTA))

Studying the processes involved in the atmospheric escape of short-period gaseous exoplanets is a key stake in our understanding of the formation, evolution, and population of exoplanets in general. A famous example is the so-called "sub-Neptune desert", for which atmospheric escape is believed to play a crucial role. Since recent years, ground-based high-resolution spectroscopy in the near-infrared allows us to probe the atmospheric escape of transiting exoplanets through the observation of the metastable He triplet lines at 1083.3nm, providing us with a new window for atmospheric escape in addition to the observation of H lines in UV and visible. With a high spectral resolution power of 70 000 and a large continuous spectral range between 0.9 and 2.5 microns, the near-infrared spectro-polarimeter SPIRou on the CFHT is a powerful instrument for exoplanet atmosphere characterization since its first light in 2018. I will present the data reduction and modeling methodology classically used for ground-based atmospheric escape characterization in the infrared, along with new constraints regarding atmospheric escape in fifteen transiting short-period exoplanets ranging from hot Jupiters to sub-Neptune observed with the SPIRou instrument.

Exploring the magnetic and cloudy properties of late-M and early L dwarfs via low resolution spectro-polarimetry ( Paulo Miles Pérez,  CAB (CSIC-INTA))

We will present our recent phase-resolved monitoring of the M8.5 dwarf LSR J1835+3259 and the L3.5 dwarf LSPM J0036+1821 by using low-resolution spectro-polarimetry at optical wavelengths. Our data reveal that both ultra-cool dwarfs exhibit strong peaks of linear polarization (>2%) that coincide with the intense, periodic aurorae seen at radio wavelengths. This correlation suggests that these phenomena are related, likely indicating a common magnetic origin, which opens a new window in the study of magnetism in the substellar regime.

Exoplanetary systems around M dwarfs with radial velocities: use of multidimensional Gaussian process to quantify the stellar noise ( Javier Banegas Paredes,  Universidad Complutense de Madrid (UCM))

In order to find Earth-like planets in the habitable zone of M dwarfs, it becomes essential to quantify the stellar noise in the radial velocity (RV) data in order to measure planetary signals. This is why the use of multidimensional Gaussian processes can be a clear evolution towards the study and characterisation of exoplanets and their host stars, this will be done using the pyaneti software. To do so, we will use RV data and spectroscopic activity indicators (FWHM, Hα) from CARMENES and ESPRESSO simultaneously for three already studied planetary systems: GJ 3779, GJ 338 B and GJ 1002. With our spectroscopic analysis we could model the stellar activity by determining the stellar rotation period and also obtain the planetary parameters of the exoplanets.

Confirmation of low-mass companion binaries from Gaia ( MariCruz Galvez Ortiz,  CAB (CSIC-INTA))

After a discussion during the MAESM meeting in 2022, we began investigating stellar multiplicity in the low-mass regime using Gaia data and virtual observatory tools, searching for low-mass stars that may have companions. From the 1843 sources listed as astrometric binary systems, which are composed of potentially late-type components (including brown dwarfs and planetary-mass objects) published by the Gaia Collaboration et al. (2022), we identified 7 candidates that show lower-temperature/mass companions. Here, we present an update with the results of our ongoing spectroscopic follow-up.

Stellar wind impact on early Hydrogen atmospheres around Earth-like exoplanets ( Ada Canet,  Universidad Complutense de Madrid (UCM))

Stellar rotation at early stages plays a fundamental role in the survival of primordial atmospheres on Earth-mass exoplanets. Earth-like planets orbiting rapidly rotating stars may undergo complete atmospheric photoevaporation within the first few hundred million years due to increased stellar XUV radiation, while those around slowly rotating stars are expected to retain their primordial envelopes more easily. In addition to stellar radiation, stellar winds contribute to the erosion of these primordial atmospheres, affecting their shape, extent, and causing further atmospheric losses. In this paper, we analyze the impact of activity-dependent stellar winds on primordial atmospheres to assess how significantly these winds influence planetary evolution at early stages. We conducted 3D magnetohydrodynamical (MHD) simulations of photoevaporating atmospheres around unmagnetized Earth-mass planets between 50 and 500 Myr, examining the combined evolution of stellar winds and atmospheres for both fast- and slow-rotating stars. Our results show considerable changes in the evolution of primordial atmospheres around fast-rotating stars, with a significant reduction in atmospheric extent at early ages. In contrast, atmospheres affected by the stellar winds of slow-rotating stars remain mostly unchanged. The interaction between magnetized stellar winds and the ionized upper atmospheres of these planets allows for the examination of different MHD structures, such as double-bow shocks and induced magnetospheres. Finally, hot plasma emission in ultraviolet wavelengths from the formed MHD structures in the vicinity of these newborn planets is evaluated, in order to predict its detectability with future large infrastructures like HWO.

Looking on the Bright Side: Eclipse Mapping the Dayside Atmospheres of Transiting Exoplanets ( Daniel Valentine,  ESA - ESTEC)

A great deal can be learned about exoplanets through studying their atmospheres. However, the data quality of previous missions limited our inferences to 1D bulk constraints, hindering the extent of our characterisation. The exquisite quality of JWST data now facilitates multidimensional characterisation, which is revolutionising our understanding of these foreign worlds. Using the "rising star" technique of eclipse mapping, we can now spatially resolve the 3D dayside emission profiles of transiting exoplanets, revealing their intricate thermal structure, dynamics, and circulation, granting us invaluable insight into their global climates. I will present the application of this technique to the hot Jupiter WASP-17b with JWST, and close with compelling future prospects using Ariel.

Esa Sky Demo

Abstract not available.