Thomas Fauchez
A5076799006- Stellar, planetary, and galactic studies
- Atmospheric Ozone and Climate
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Atmospheric aerosols and clouds
- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Planetary Science and Exploration
- Spectroscopy and Laser Applications
- Calibration and Measurement Techniques
- Space Exploration and Technology
- Astrophysics and Star Formation Studies
- Scientific Research and Discoveries
- Climate variability and models
- Space Science and Extraterrestrial Life
- Astronomical Observations and Instrumentation
- Spacecraft Design and Technology
- Isotope Analysis in Ecology
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Molecular Spectroscopy and Structure
- Infrared Target Detection Methodologies
- Regional Economic and Spatial Analysis
- Meteorological Phenomena and Simulations
Goddard Space Flight Center
2017-2024
American University
2022-2024
NASA Exoplanet Science Institute
2020-2024
Centre National de la Recherche Scientifique
2013-2023
Institut d'Astrophysique de Paris
2023
University of Geneva
2023
Universities Space Research Association
2017-2022
Planetary Science Institute
2022
University of Washington
2022
Max Planck Society
2018
Abstract The two-planet transiting system LHS 1140 has been extensively observed since its discovery in 2017, notably with Spitzer, HST, TESS, and ESPRESSO, placing strong constraints on the parameters of M4.5 host star small temperate exoplanets, b c. Here, we reanalyze ESPRESSO observations novel line-by-line framework designed to fully exploit radial velocity content a stellar spectrum while being resilient outlier measurements. improved velocities, combined updated parameters,...
Abstract The TRAPPIST-1 system, consisting of an ultracool host star having seven known Earth-sized planets, will be a prime target for atmospheric characterization with the James Webb Space Telescope ( JWST ). However, detectability molecular species may severely impacted by presence clouds and/or hazes. In this work, we perform 3D general circulation model (GCM) simulations LMD-G supplemented 1D photochemistry at terminator Atmos to simulate several possible atmospheres TRAPPIST-1e, 1f,...
Abstract We present the discovery and validation of a three-planet system orbiting nearby (31.1 pc) M2 dwarf star TOI-700 (TIC 150428135). lies in TESS continuous viewing zone Southern Ecliptic Hemisphere; observations spanning 11 sectors reveal three planets with radii ranging from 1 R ⊕ to 2.6 orbital periods 9.98 37.43 days. Ground-based follow-up combined diagnostic vetting tests enables us rule out common astrophysical false-positive scenarios validate planets. The outermost planet, d,...
Abstract To identify promising exoplanets for atmospheric characterization and to make the best use of observational data, a thorough understanding their atmospheres is needed. Three-dimensional general circulation models (GCMs) are one most comprehensive tools available this task will be used interpret observations temperate rocky exoplanets. Due parameterization choices made in GCMs, they can produce different results, even same planet. Employing four widely exoplanetary GCMs—ExoCAM,...
Abstract The TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI) is a community project that aims to quantify how differences in general circulation models (GCMs) could impact the climate prediction for TRAPPIST-1e and, subsequently, its atmospheric characterization transit. Four GCMs have participated THAI: ExoCAM, LMD-Generic, ROCKE-3D, and UM. This paper, focused on simulated observations, third part of trilogy, following analysis two land planet scenarios (Part I) aquaplanet II). Here...
Abstract The TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI) project was initiated to compare 3D climate models that are commonly used for predicting theoretical climates of habitable zone extrasolar planets. One the core studied as part THAI is ExoCAM, an independently curated exoplanet branch National Center Atmospheric Research Community Earth System Model (CESM), version 1.2.1. ExoCAM has been studying atmospheres terrestrial planets around a variety stars. To accompany and...
Abstract With the commissioning of powerful, new-generation telescopes such as James Webb Space Telescope (JWST) and ground-based Extremely Large Telescopes, first characterization a high molecular weight atmosphere around temperate rocky exoplanet is imminent. Atmospheric simulations synthetic observables target exoplanets are essential to prepare interpret these observations. Here we report results part TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI) project, which compares 3D...
Abstract LHS 1140 b is the second-closest temperate transiting planet to Earth with an equilibrium temperature low enough support surface liquid water. At 1.730 ± 0.025 R ⊕ , falls within radius valley separating H 2 -rich mini-Neptunes from rocky super-Earths. Recent mass and revisions indicate a bulk density significantly lower than expected for Earth-like interior, suggesting that could be either mini-Neptune small envelope of hydrogen (∼0.1% by mass) or water world (9%–19% mass)....
Context. Asteroid modeling efforts in the last decade resulted a comprehensive dataset of almost 400 convex shape models and their rotation states. These already provided deep insight into physical properties main-belt asteroids or large collisional families. Going finer detail (e.g., smaller families, with sizes ≲20 km) requires knowledge parameters more objects.
Planets similar to Earth - but slightly more irradiated are expected enter into a runaway greenhouse state, where all surface water rapidly evaporates, forming an optically thick H2O-dominated atmosphere. For Earth, this extreme climate transition is thought occur for ~6% increase only of the solar luminosity, though exact limit at which would still highly debated topic. In general, believed be fundamental process in evolution Earth-size, temperate planets. Using 1-D radiative-convective...
We are on the verge of characterizing atmospheres terrestrial exoplanets in habitable zones M dwarf stars. Due to their large planet-to-star radius ratios and higher frequency transits, orbiting stars favorable for transmission spectroscopy. In this work, we quantify effect that water clouds have amplitude vapor spectral features To do so, make synthetic spectra from general circulation model (GCM) experiments tidally locked planets. improve upon previous work by considering how varying a...
Abstract The era of atmospheric characterization terrestrial exoplanets is just around the corner. Modeling prior to observations crucial in order predict observational challenges and prepare for data interpretation. This paper presents report TRAPPIST Habitable Atmosphere Intercomparison workshop (2020 September 14–16). A review climate models parameterizations processes on exoplanets, model advancements, limitations, as well direction future development, was discussed. We hope that this...
We present the discovery of an Earth-mass planet ( M b sin i = 1.26 ± 0.21 ⊕ ) on a 15.6 d orbit relatively nearby ~ 9.6 pc) and low-mass (0.167 0.011 ⊙ M5.0 V star, Wolf 1069. Sitting at separation 0.0672 0.0014 au away from host star puts 1069 in habitable zone (HZ), receiving incident flux S 0.652 0.029 . The planetary signal was detected using telluric-corrected radial-velocity (RV) data CARMENES spectrograph, amounting to total 262 spectroscopic observations covering almost four years....
Understanding the set of conditions that allow rocky planets to have liquid water on their surface, in form lakes, seas, or oceans, is a major scientific step determining fraction potentially suitable for emergence and development life as we know it Earth. This effort also necessary define refine what known habitable zone (HZ) order guide search exoplanets likely harbor remotely detectable forms. To date, most numerical climate studies this topic focused maintain but not them first place....
Abstract Radiative transfer (RT) models are critical in the interpretation of exoplanetary spectra, simulating exoplanet climates, and when designing specifications future flagship observatories. However, most differ methodologies input data, which can lead to significantly different spectra. In this paper, we present experimental protocol Modeling Atmospheric Lines By Exoplanet Community (MALBEC) project. MALBEC is an model intercomparison project that belongs Climates Using Interactive...
We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three terrestrial-sized planets transiting L 98-59 (TOI-175, TIC 307210830) -- a bright M dwarf at distance 10.6 pc. Using Gaia-measured and broad-band photometry we find that host star is an M3 dwarf. Combined with TESS transits from sectors, corresponding stellar parameters yield planet radii ranging 0.8REarth to 1.6REarth. All have short orbital periods, 2.25 7.45 days outer pair just wide 2:1 period resonance....
Abstract The search for water-rich Earth-sized exoplanets around low-mass stars is rapidly gaining attention because they represent the best opportunity to characterize habitable planets in near future. Understanding atmospheres of these and determining optimal strategy characterizing them through transmission spectroscopy with our upcoming instrumentation essential order constrain their environments. For this study, we present simulated spectra tidally locked ocean-covered late-M mid-K...
Abstract Discoveries of terrestrial, Earth-sized exoplanets that lie within the habitable zone (HZ) their host stars continue to occur at increasing rates. Transit spectroscopy can potentially enable detection molecular signatures from such worlds, providing an indication presence atmosphere and its chemical composition, including gases indicative a biosphere. Such planets around nearby M-dwarf stars—such as TRAPPIST-1—provide relatively good signal, high signal-to-noise ratio, frequent...
Earth-like, potentially habitable exoplanets are prime targets in the search for extraterrestrial life. Information about their atmosphere and surface can be derived by analyzing light of parent star reflected planet. We investigate influence albedo $A_{\rm s}$, optical thickness $b_{\rm cloud}$ altitude water clouds, mixing ratio $\eta$ biosignature O$_2$ on strength A-band (around 760 nm) flux polarization spectra starlight Earth-like exoplanets. Our computations horizontally homogeneous...
We present self-consistent three-dimensional climate simulations of possible habitable states for the newly discovered Habitable Zone Earth-sized planet, TOI-700 d. explore a variety atmospheric compositions, pressures, and rotation both ocean-covered completely desiccated planets in order to assess planet's potential habitability. For all 20 our simulated cases, we use model outputs synthesize transmission spectra, combined-light integrated broadband phase curves. These...
Nitrous oxide (N2O) -- a product of microbial nitrogen metabolism is compelling exoplanet biosignature gas with distinctive spectral features in the near- and mid-infrared, only minor abiotic sources on Earth. Previous investigations N2O as have examined scenarios using Earthlike mixing ratios or surface fluxes, those inferred from Earth's geologic record. However, biological fluxes could be substantially higher, due to lack metal catalysts if last step denitrification that yields N2 had...
Abstract. This paper presents a study of the impact cirrus cloud heterogeneities on thermal infrared brightness temperatures at top atmosphere (TOA). Realistic 3-D cirri are generated by generator based simplified thermodynamic and dynamic equations control invariant scale properties. The radiative transfer is simulated with Monte Carlo model for three typical spectral bands in atmospheric window. Comparisons TOA resulting from 1-D show significant differences optically thick (τ > 0.3 532...
The presence of chlorofluorocarbons (CFCs) in Earth's atmosphere is a direct result technology. Ozone-depleting CFCs have been banned by most countries, but some persistent elevated concentrations due to their long stratospheric lifetimes. are effective greenhouse gases and could serve as remotely detectable spectral signature Here we use three-dimensional climate model synthetic spectrum generator assess the detectability CFC-11 CFC-12 technosignature on exoplanets. We consider case...