Publications (71)
3D modeling of GJ1214b's atmosphere: vertical mixing driven by an anti-Hadley circulation
Benjamin Charnay, Victoria Meadows, Jérémy Leconte
GJ1214b is a warm sub-Neptune transiting in front of a nearby M dwarf star. Recent observations indicate the presence of high and thick clouds or haze whose presence requires stron…
The radiative and dynamical impact of clouds in the atmosphere of the hot Jupiter WASP-43 b
Lucas Teinturier, Benjamin Charnay, Aymeric Spiga +6
Hot Jupiters exhibit large day-night temperature contrasts. Their cooler nightsides are thought to host clouds. However, the exact nature of these clouds, their spatial distributio…
Early Mars' habitability and global cooling by H2-based methanogens
Boris Sauterey, Benjamin Charnay, Antonin Affholder +2
During the Noachian, Mars' crust may have provided a favorable environment for microbial life. The porous brine-saturated regolith would have created a physical space sheltered fro…
A self-consistent cloud model for brown dwarfs and young giant exoplanets: comparison with photometric and spectroscopic observations
Benjamin Charnay, Bruno Bézard, Jean-Loup Baudino +3
We developed a simple, physical and self-consistent cloud model for brown dwarfs and young giant exoplanets. We compared different parametrisations for the cloud particle size, by…
A warm or a cold early Earth? New insights from a 3-D climate-carbon model
Benjamin Charnay, Guillaume Le Hir, Frédéric Fluteau +2
Oxygen isotopes in marine cherts have been used to infer hot oceans during the Archean with temperatures between 60°C (333 K) and 80°C (353 K). Such climates are challenging for…
Next-generation Exo-REM atmospheric models: application to VHS 1256 b to emulate patchy clouds
Alice Radcliffe, Benjamin Charnay, Anne-Marie Lagrange +7
Condensate clouds are a defining feature of brown dwarf and exoplanet atmospheres, producing a broad range of colours on the CMD and giving rise to spectral features such as the di…
On the synergetic use of Ariel and JWST for exoplanet atmospheric science
Quentin Changeat, Pierre-Olivier Lagage, Giovanna Tinetti +27
This paper explores the potential for strategic synergies between the JWST and the Ariel telescopes, two flagship observatories poised to revolutionise the study of exoplanet atmos…
Is the Pale Blue Dot unique? Optimized photometric bands for identifying Earth-like exoplanets
Joshua Krissansen-Totton, Edward W. Schwieterman, Benjamin Charnay +4
The next generation of ground and space-based telescopes will image habitable planets around nearby stars. A growing literature describes how to characterize such planets with spec…
Resolving core-envelope degeneracies in giant planets and sub-Neptunes: constraining the equivalence in the presence of dilute gradients
Christian Wilkinson, Benjamin Charnay, Stéphane Mazevet +4
The widespread recognition of dilute, "fuzzy" cores in giant planets and massive volatile mantles in sub-Neptunes has made interior modelling a highly degenerate, multi-dimensional…
CAMEMBERT: A Mini-Neptunes GCM Intercomparison, Protocol Version 1.0. A CUISINES Model Intercomparison Project
Duncan A. Christie, Elspeth K. H. Lee, Hamish Innes +19
With an increased focus on the observing and modelling of mini-Neptunes, there comes a need to better understand the tools we use to model their atmospheres. In this paper, we pres…
ARES III: Unveiling the Two Faces of KELT-7 b with HST WFC3
William Pluriel, Niall Whiteford, Billy Edwards +24
We present the analysis of the hot-Jupiter KELT-7b using transmission and emission spectroscopy from the Hubble Space Telescope (HST), both taken with the Wide Field Camera 3 (WFC3…
Exoplanet Diversity in the Era of Space-based Direct Imaging Missions
Ravi Kopparapu, Eric Hebrard, Rus Belikov +55
This whitepaper discusses the diversity of exoplanets that could be detected by future observations, so that comparative exoplanetology can be performed in the upcoming era of larg…
Titan's past and future: 3D modeling of a pure nitrogen atmosphere and geological implications
Benjamin Charnay, François Forget, Gabriel Tobie +2
Several clues indicate that Titan's atmosphere has been depleted in methane during some period of its history, possibly as recently as 0.5-1 billion years ago. It could also happen…
Nightside clouds and disequilibrium chemistry on the hot Jupiter WASP-43b
Taylor J. Bell, Nicolas Crouzet, Patricio E. Cubillos +80
Hot Jupiters are among the best-studied exoplanets, but it is still poorly understood how their chemical composition and cloud properties vary with longitude. Theoretical models pr…
Mapping of Jupiter's tropospheric NH abundance using ground-based IRTF/TEXES observations at 5 m
Doriann Blain, Thierry Fouchet, Thomas Greathouse +8
We report on results of an observing campaign to support the Juno mission. At the beginning of 2016, using TEXES (Texas Echelon cross-dispersed Echelle Spectrograph), mounted on th…
1D atmospheric study of the temperate sub-Neptune K2-18b
Doriann Blain, Benjamin Charnay, Bruno Bézard
The atmospheric composition of exoplanets with masses between 2 and 10 M is poorly understood. In that regard, the sub-Neptune K2-18b, which is subject to Earth-like stell…
First JWST thermal phase curves of temperate terrestrial exoplanets reveal no thick atmosphere around TRAPPIST-1 b and c
Michaël Gillon, Elsa Ducrot, Taylor J. Bell +30
We report JWST/MIRI 15 m phase curves of TRAPPIST-1 b and c, revealing thermal emission consistent with their irradiation levels, assuming no efficient heat redistribution. We…
Breaking degeneracies in exoplanetary parameters through self-consistent atmosphere-interior modelling
Christian Wilkinson, Benjamin Charnay, Stéphane Mazevet +5
Context: A new generation of instruments (e.g., JWST, ELTs, PLATO and Ariel) is providing atmospheric spectra and mass/radius measurements for large exoplanet populations, challeng…
X-SHYNE: X-shooter spectra of young exoplanet analogs. I. A medium-resolution 0.65-2.5 one-shot spectrum of VHS\,1256-1257 b
Simon Petrus, Gaël Chauvin, Mickaël Bonnefoy +10
We present simultaneous 0.65-2.5 microns medium resolution (3300 < R < 8100) VLT/X-Shooter spectra of the young low-mass (19+/-5MJup) L-T transition object VHS 1256-1257 b, a known…
Exo-Milankovitch Cycles II: Climates of G-dwarf Planets in Dynamically Hot Systems
Russell Deitrick, Rory Barnes, Cecilia Bitz +6
Using an energy balance model with ice sheets, we examine the climate response of an Earth-like planet orbiting a G dwarf star and experiencing large orbital and obliquity variatio…
A 3D picture of moist-convection inhibition in hydrogen-rich atmospheres: Implications for K2-18 b
Jérémy Leconte, Aymeric Spiga, Noé Clément +9
While small, Neptune-like planets are among the most abundant exoplanets, our understanding of their atmospheric structure and dynamics remains sparse. In particular, many unknowns…
A roadmap for the atmospheric characterization of terrestrial exoplanets with JWST
TRAPPIST-1 JWST Community Initiative, :, Julien de Wit +80
Ultra-cool dwarf stars are abundant, long-lived, and uniquely suited to enable the atmospheric study of transiting terrestrial companions with JWST. Amongst them, the most prominen…
Formation and dynamics of water clouds on temperate sub-Neptunes: The example of K2-18b
Benjamin Charnay, Doriann Blain, Bruno Bézard +3
Hubble (HST) spectroscopic transit observations of the temperate sub-Neptune K2-18b were interpreted as the presence of water vapour with potential water clouds. 1D modelling studi…
Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Charles Cadieux, René Doyon, Ryan J. MacDonald +20
LHS 1140 b is the second-closest temperate transiting planet to the Earth with an equilibrium temperature low enough to support surface liquid water. At 1.7300.025 R,…
ARES V: No Evidence For Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b
Lorenzo V. Mugnai, Darius Modirrousta-Galian, Billy Edwards +25
We present a study on the spatially scanned spectroscopic observations of the transit of GJ 1132 b, a warm (500 K) Super-Earth (1.13 R) that was obtained with the G1…
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems V: Do Self-Consistent Atmospheric Models Represent JWST Spectra? A Showcase With VHS 1256 b
Simon Petrus, Niall Whiteford, Polychronis Patapis +119
The unprecedented medium-resolution (R~1500-3500) near- and mid-infrared (1-18um) spectrum provided by JWST for the young (140+/-20Myr) low-mass (12-20MJup) L-T transition (L7) com…
A reduced chemical scheme for modelling warm to hot hydrogen-dominated atmospheres
Olivia Venot, Roda Bounaceur, Michel Dobrijevic +5
Three dimensional models that account for chemistry are useful tools to predict the chemical composition of (exo)planet and brown dwarf atmospheres and interpret observations of fu…
VLTI/GRAVITY Observations of AF Lep b: Preference for Circular Orbits, Cloudy Atmospheres, and a Moderately Enhanced Metallicity
William O. Balmer, Kyle Franson, Antoine Chomez +26
Direct imaging observations are biased towards wide-separation, massive companions that have degenerate formation histories. Although the majority of exoplanets are expected to for…
Gravitational atmospheric tides as a probe of Titan's interior: Application to Dragonfly
Benjamin Charnay, Gabriel Tobie, Sébastien Lebonnois +1
Context: Saturn's massive gravity is expected to causes a tide in Titan's atmosphere, producing a surface pressure variation through the orbit of Titan and tidal winds in the tropo…
The Effect of Orbital Configuration on the Possible Climates and Habitability of Kepler-62f
Aomawa L. Shields, Rory Barnes, Eric Agol +3
As lower-mass stars often host multiple rocky planets, gravitational interactions among planets can have significant effects on climate and habitability over long timescales. Here…
3D climate modeling of close-in land planets: Circulation patterns, climate moist bistability and habitability
Jérémy Leconte, Francois Forget, Benjamin Charnay +3
The inner edge of the classical habitable zone is often defined by the critical flux needed to trigger the runaway greenhouse instability. This 1D notion of a critical flux, howeve…
Water Condensation Zones around Main Sequence Stars
Martin Turbet, Thomas J. Fauchez, Jeremy Leconte +10
Understanding the set of conditions that allow rocky planets to have liquid water on their surface -- in the form of lakes, seas or oceans -- is a major scientific step to determin…
TRAPPIST Habitable Atmosphere Intercomparison (THAI) workshop report
Thomas J. Fauchez, Martin Turbet, Denis E. Sergeev +31
The era of atmospheric characterization of terrestrial exoplanets is just around the corner. Modeling prior to observations is crucial in order to predict the observational challen…
The Pale Orange Dot: The Spectrum and Habitability of Hazy Archean Earth
Giada Arney, Shawn D. Domagal-Goldman, Victoria S. Meadows +6
Recognizing whether a planet can support life is a primary goal of future exoplanet spectral characterization missions, but past research on habitability assessment has largely ign…
Panchromatic View of the Frigid Jovian Exoplanet COCONUTS-2 b
Matthieu Ravet, Mickaël Bonnefoy, Gaël Chauvin +24
We use a high signal-to-noise MIRI-LRS spectrum (5.45 - 11 m, R ) of COCONUTS-2~b revealing prominent molecular features of HO, CH and NH. This datase…
Clouds as the driver of variability and colour changes in brown dwarf atmospheres
Lucas Teinturier, Benjamin Charnay, Aymeric Spiga +1
Brown dwarfs are massive, giant exoplanet analogues subject to variability and colour changes, known as the L/T transition, fundamental for their thermal evolution. The drivers of…
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems. VII. Molecular Mapping Performance with JWST/MIRI MRS: VHS 1256 b as a case study
Mathilde Mâlin, Anthony Boccaletti, Benjamin Charnay +29
VHS 1256 b was the first planetary-mass companion to be observed with the James Webb Space Telescope's Mid-Infrared Instrument (JWST/MIRI) using the Medium-Resolution Spectrometer…
A new atmospheric characterization of the sub-stellar companion HR\,2562\,B with JWST/MIRI observations
Nicolás Godoy, Elodie Choquet, Eugene Serabyn +8
Context: HR2562B is a planetary-mass companion located 0.56arcsec (19au) from its host star. It is one of a few L/T transitional objects orbiting a young star. This companion provi…
Effects of a fully 3D atmospheric structure on exoplanet transmission spectra: retrieval biases due to day-night temperature gradients
Anthony Caldas, Jérémy Leconte, Franck Selsis +4
Transmission spectroscopy provides us with information on the atmospheric properties at the limb, which is often intuitively assumed to be a narrow annulus around the planet. Conse…
CO2 condensation is a serious limit to the deglaciation of Earth-like planets
Martin Turbet, Francois Forget, Jeremy Leconte +2
It is widely believed that the carbonate-silicate cycle is the main agent to trigger deglaciations by CO greenhouse warming on Earth and on Earth-like planets when they get in…
First unambiguous detection of ammonia in the atmosphere of a planetary mass companion with JWST/MIRI coronagraphs
Mathilde Mâlin, Anthony Boccaletti, Clément Perrot +28
The newly accessible mid-infrared (MIR) window offered by the James Webb Space Telescope (JWST) for exoplanet imaging is expected to provide valuable information to characterize th…
Possible favored Great Oxidation Event scenario on exoplanets around M-Stars with the example of TRAPPIST-1e
Adam Y. Jaziri, Nathalie Carrasco, Benjamin Charnay
The Great Oxidation Event (GOE), which marked the transition from an anoxic to an oxygenated atmosphere, occurred 2.4 billion years ago on Earth, several hundreds of millions of ye…
Latitudinal chemical and cloud variations in the atmosphere of a brown dwarf
Benjamin Charnay, Sam de Regt, Matthieu Ravet +8
The paper introduces a technique called Differential Molecular Rotational Broadening to detect latitudinal chemical differences in brown dwarf atmospheres, and applies it to VLT-CR…
Exploring the faint young Sun problem and the possible climates of the Archean Earth with a 3-D GCM
Benjamin Charnay, François Forget, Robin Wordsworth +4
Different solutions have been proposed to solve the "faint young Sun problem", defined by the fact that the Earth was not fully frozen during the Archean despite the fainter Sun. M…
The beta Pictoris system: Setting constraints on the planet and the disk structures at mid-IR wavelengths with NEAR
Nour Skaf, Anthony Boccaletti, Eric Pantin +26
[abridged] We analyzed mid-infrared high-contrast coronagraphic images of the beta Pictoris system, taking advantage of the NEAR experiment using the VLT/VISIR instrument. The goal…
Exo-Milankovitch Cycles I: Orbits and Rotation States
Russell Deitrick, Rory Barnes, Thomas R. Quinn +3
The obliquity of the Earth, which controls our seasons, varies by only ~2.5 degrees over ~40,000 years, and its eccentricity varies by only ~0.05 over 100,000 years. Nonetheless, t…
Increased insolation threshold for runaway greenhouse processes on Earth like planets
Jérémy Leconte, François Forget, Benjamin Charnay +2
Because the solar luminosity increases over geological timescales, Earth climate is expected to warm, increasing water evaporation which, in turn, enhances the atmospheric greenhou…
New Mass and Radius Constraints on the LHS 1140 Planets -- LHS 1140 b is Either a Temperate Mini-Neptune or a Water World
Charles Cadieux, Mykhaylo Plotnykov, René Doyon +43
The two-planet transiting system LHS 1140 has been extensively observed since its discovery in 2017, notably with , HST, TESS, and ESPRESSO, placing strong constraints on…
A survey of exoplanet phase curves with Ariel
Benjamin Charnay, Joao M. Mendonça, Laura Kreidberg +12
The ESA-Ariel mission will include a tier dedicated to exoplanet phase curves corresponding to ~10% of the science time. We present here the current observing strategy for studying…
ARES II: Characterising the Hot Jupiters WASP-127 b, WASP-79 b and WASP-62 b with HST
Nour Skaf, Michelle Fabienne Bieger, Billy Edwards +24
This paper presents the atmospheric characterisation of three large, gaseous planets: WASP-127b, WASP-79b and WASP-62b. We analysed spectroscopic data obtained with the G141 grism…
Librational response of a deformed 3-layer Titan perturbed by non-keplerian orbit and atmospheric couplings
Andy Richard, Nicolas Rambaux, Benjamin Charnay
The analyses of Titan's gravity field obtained by Cassini space mission suggest the presence of an internal ocean beneath its icy surface. The characterization of the geophysical p…
X-SHYNE: X-Shooter spectra of young exoplanet analogs II. Presentation and analysis of the full library
Simon Petrus, Gaël Chauvin, Mickaël Bonnefoy +29
The X-SHYNE library is a homogeneous sample of 43 medium-resolution (R=8000) infrared (0.3-2.5um) spectra of young (<500Myr), low-mass (<20Mjup), and cold (Teff=600-2000K) isolated…
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems VIII: patchy forsterite and enstatite clouds in the atmosphere of VHS 1256 b, retrieval lessons learned and outlook to the future
Niall Whiteford, Jacqueline K. Faherty, Ben Burningham +123
JWST defines a new era for the data-driven approach of retrieval modelling, which has become a cornerstone tool for the statistical inference of exoplanetary and brown dwarf proper…
ARES I: WASP-76 b, A Tale of Two HST Spectra
Billy Edwards, Quentin Changeat, Robin Baeyens +25
We analyse the transmission and emission spectra of the ultra-hot Jupiter WASP-76b, observed with the G141 grism of the Hubble Space Telescope's Wide Field Camera 3 (WFC3). We redu…
Dynamics of the Great Oxidation Event from a 3D photochemical-climate model
Adam Yassin Jaziri, Benjamin Charnay, Franck Selsis +2
From the Archean toward the Proterozoic, the Earth's atmosphere underwent a major shift from anoxic to oxic conditions, around 2.4 to 2.1 Gyr, known as the Great Oxidation Event (G…
3D modeling of GJ1214b's atmosphere: formation of inhomogeneous high clouds and observational implications
Benjamin Charnay, Victoria Meadows, Amit Misra +2
The warm sub-Neptune GJ1214b has a featureless transit spectrum which may be due to the presence of high and thick clouds or haze. Here, we simulate the atmosphere of GJ1214b with…
Warm Jupiters around M-dwarfs are great opportunities for extensive chemical, cloud and haze characterisation with JWST
Lucas Teinturier, Elsa Ducrot, Benjamin Charnay
The population of short-period giant exoplanets around M-dwarf stars is slowly rising. These planets present an extraordinary opportunity for atmospheric characterisation and defy…
Methane as a dominant absorber in the habitable-zone sub-Neptune K2-18 b
Bruno Bézard, Benjamin Charnay, Doriann Blain
In their Letter, Tsiaras et al. reported the detection of water vapour in the atmosphere of K2-18 b, an exoplanet of 7 to 10 Earth masses located in the habitable zone of an M-dwar…
Simultaneous, Multi-Wavelength Variability Characterization of the Free-Floating Planetary Mass Object PSO J318.5-22
Beth Biller, Johanna Vos, Esther Buenzli +15
We present simultaneous HST WFC3 + Spitzer IRAC variability monitoring for the highly-variable young (20 Myr) planetary-mass object PSO J318.5-22. Our simultaneous HST + Spit…
Science goals and new mission concepts for future exploration of Titan's atmosphere geology and habitability: Titan POlar Scout/orbitEr and In situ lake lander and DrONe explorer (POSEIDON)
Sébastien Rodriguez, Sandrine Vinatier, Daniel Cordier +61
In response to ESA Voyage 2050 announcement of opportunity, we propose an ambitious L-class mission to explore one of the most exciting bodies in the Solar System, Saturn largest m…
ARES IV: Probing the atmospheres of the two warm small planets HD 106315 c and HD 3167 c with the HST/WFC3 camera
Gloria Guilluy, Amélie Gressier, Sam Wright +27
We present an atmospheric characterization study of two medium sized planets bracketing the radius of Neptune: HD 106315 c (R=4.98 0.23 R) and HD 3167 c…
Coevolution of primitive methane cycling ecosystems and early Earth atmosphere and climate
Boris Sauterey, Benjamin Charnay, Antonin Affholder +2
The history of the Earth has been marked by major ecological transitions, driven by metabolic innovation, that radically reshaped the composition of the oceans and atmosphere. The…
Is the faint young Sun problem for Earth solved?
Benjamin Charnay, Eric T. Wolf, Bernard Marty +1
Stellar evolution models predict that the solar luminosity was lower in the past, typically 20-25 % lower during the Archean (3.8-2.5 Ga). Despite the fainter Sun, there is strong…
A medium-resolution spectrum of the exoplanet HIP 65426 b
Simon Petrus, Mickaël Bonnefoy, Gaël Chauvin +18
Medium-resolution integral-field spectrographs (IFS) coupled with adaptive-optics such as Keck/OSIRIS, VLT/MUSE, or SINFONI are appearing as a new avenue for enhancing the detectio…
Formation of secondary atmospheres on terrestrial planets by late disk accretion
Quentin Kral, Jeanne Davoult, Benjamin Charnay
Recently, gas disks have been discovered around main sequence stars well beyond the usual protoplanetary disk lifetimes (i.e., > 10 Myrs), when planets have already formed. These g…
Science goals and mission concepts for a future orbital and in situ exploration of Titan
Sébastien Rodriguez, Sandrine Vinatier, Daniel Cordier +27
In this white paper, we present a cross-section of important scientific questions that remain partially or completely unanswered, ranging from Titan exosphere to the deep interior,…
Gliese 581d is the first discovered terrestrial-mass exoplanet in the habitable zone
Robin Wordsworth, François Forget, Franck Selsis +3
It has been suggested that the recently discovered exoplanet GJ581d might be able to support liquid water due to its relatively low mass and orbital distance. However, GJ581d recei…
Ariel: Enabling planetary science across light-years
Giovanna Tinetti, Paul Eccleston, Carole Haswell +313
Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. Durin…
Constraints on the possible atmospheres on TRAPPIST-1 b: insights from 3D climate modeling
Alice Maurel, Martin Turbet, Elsa Ducrot +13
JWST observations of the secondary eclipse of TRAPPIST-1 b at 12.8 and 15 microns revealed a very bright dayside. These measurements are consistent with an absence of atmosphere. P…
Methane storms as a driver of Titan's dune orientation
Benjamin Charnay, Erika Barth, Scot Rafkin +5
Titan's equatorial regions are covered by eastward propagating linear dunes. This direction is opposite to mean surface winds simulated by Global Climate Models (GCMs), which are o…
Possible Atmospheric Diversity of Low Mass Exoplanets, some Central Aspects
John Lee Grenfell, Jeremy Leconte, François Forget +9
Exoplanetary science continues to excite and surprise with its rich diversity. We discuss here some key aspects potentially influencing the range of exoplanetary terrestrial-type a…