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1. Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS

Author: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L’Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, and Diana Valencia
Subjects: Exoplanets, Habitable planets, Planetary atmospheres, Super Earths, Ocean planets, Mini Neptunes, Astrophysics, QB460-466
Abstract: LHS 1140 b is the second-closest temperate transiting planet to Earth with an equilibrium temperature low enough to support surface liquid water. At 1.730 ± 0.025 R _⊕ , LHS 1140 b falls within the radius valley separating H _2 -rich mini-Neptunes from rocky super-Earths. Recent mass and radius revisions indicate a bulk density significantly lower than expected for an Earth-like rocky interior, suggesting that LHS 1140 b could be either a mini-Neptune with a small envelope of hydrogen (∼0.1% by mass) or a water world (9%–19% water by mass). Atmospheric characterization through transmission spectroscopy can readily discern between these two scenarios. Here we present two JWST/NIRISS transit observations of LHS 1140 b, one of which captures a serendipitous transit of LHS 1140 c. The combined transmission spectrum of LHS 1140 b shows a telltale spectral signature of unocculted faculae (5.8 σ ), covering ∼20% of the visible stellar surface. Besides faculae, our spectral retrieval analysis reveals tentative evidence of residual spectral features, best fit by Rayleigh scattering from a N _2 -dominated atmosphere (2.3 σ ), irrespective of the consideration of atmospheric hazes. We also show through Global Climate Models (GCMs) that H _2 -rich atmospheres of various compositions (100×, 300×, 1000× solar metallicity) are ruled out to >10 σ . The GCM calculations predict that water clouds form below the transit photosphere, limiting their impact on transmission data. Our observations suggest that LHS 1140 b is either airless or, more likely, surrounded by an atmosphere with a high mean molecular weight. Our tentative evidence of a N _2 -rich atmosphere provides strong motivation for future transmission spectroscopy observations of LHS 1140 b.
Published: 2024
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2. 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 1256–1257 b

Author: Simon Petrus, Niall Whiteford, Polychronis Patapis, Beth A. Biller, Andrew Skemer, Sasha Hinkley, Genaro Suárez, Paulina Palma-Bifani, Caroline V. Morley, Pascal Tremblin, Benjamin Charnay, Johanna M. Vos, Jason J. Wang, Jordan M. Stone, Mickaël Bonnefoy, Gaël Chauvin, Brittany E. Miles, Aarynn L. Carter, Anna Lueber, Christiane Helling, Ben J. Sutlieff, Markus Janson, Eileen C. Gonzales, Kielan K. W. Hoch, Olivier Absil, William O. Balmer, Anthony Boccaletti, Mariangela Bonavita, Mark Booth, Brendan P. Bowler, Zackery W. Briesemeister, Marta L. Bryan, Per Calissendorff, Faustine Cantalloube, Christine H. Chen, Elodie Choquet, Valentin Christiaens, Gabriele Cugno, Thayne Currie, Camilla Danielski, Matthew De Furio, Trent J. Dupuy, Samuel M. Factor, Jacqueline K. Faherty, Michael P. Fitzgerald, Jonathan J. Fortney, Kyle Franson, Julien H. Girard, Carol A. Grady, Thomas Henning, Dean C. Hines, Callie E. Hood, Alex R. Howe, Paul Kalas, Jens Kammerer, Grant M. Kennedy, Matthew A. Kenworthy, Pierre Kervella, Minjae Kim, Daniel Kitzmann, Adam L. Kraus, Masayuki Kuzuhara, Pierre-Olivier Lagage, Anne-Marie Lagrange, Kellen Lawson, Cecilia Lazzoni, Jarron M. Leisenring, Ben W. P. Lew, Michael C. Liu, Pengyu Liu, Jorge Llop-Sayson, James P. Lloyd, Bruce Macintosh, Mathilde Mâlin, Elena Manjavacas, Sebastián Marino, Mark S. Marley, Christian Marois, Raquel A. Martinez, Elisabeth C. Matthews, Brenda C. Matthews, Dimitri Mawet, Johan Mazoyer, Michael W. McElwain, Stanimir Metchev, Michael R. Meyer, Maxwell A. Millar-Blanchaer, Paul Mollière, Sarah E. Moran, Sagnick Mukherjee, Eric Pantin, Marshall D. Perrin, Laurent Pueyo, Sascha P. Quanz, Andreas Quirrenbach, Shrishmoy Ray, Isabel Rebollido, Jea Adams Redai, Bin B. Ren, Emily Rickman, Steph Sallum, Matthias Samland, Benjamin Sargent, Joshua E. Schlieder, Karl R. Stapelfeldt, Motohide Tamura, Xianyu Tan, Christopher A. Theissen, Taichi Uyama, Malavika Vasist, Arthur Vigan, Kevin Wagner, Kimberly Ward-Duong, Schuyler G. Wolff, Kadin Worthen, Mark C. Wyatt, Marie Ygouf, Alice Zurlo, Xi Zhang, Keming Zhang, Zhoujian Zhang, and Yifan Zhou
Subjects: Exoplanet atmospheres, Infrared spectroscopy, Direct imaging, L dwarfs, Nested sampling, James Webb Space Telescope, Astrophysics, QB460-466
Abstract: The unprecedented medium-resolution ( R _λ ∼ 1500–3500) near- and mid-infrared (1–18 μ m) spectrum provided by JWST for the young (140 ± 20 Myr) low-mass (12–20 M _Jup ) L–T transition (L7) companion VHS 1256 b gives access to a catalog of molecular absorptions. In this study, we present a comprehensive analysis of this data set utilizing a forward-modeling approach applying our Bayesian framework, ForMoSA . We explore five distinct atmospheric models to assess their performance in estimating key atmospheric parameters: T _eff , log( g ), [M/H], C/O, γ , f _sed , and R . Our findings reveal that each parameter’s estimate is significantly influenced by factors such as the wavelength range considered and the model chosen for the fit. This is attributed to systematic errors in the models and their challenges in accurately replicating the complex atmospheric structure of VHS 1256 b, notably the complexity of its clouds and dust distribution. To propagate the impact of these systematic uncertainties on our atmospheric property estimates, we introduce innovative fitting methodologies based on independent fits performed on different spectral windows. We finally derived a T _eff consistent with the spectral type of the target, considering its young age, which is confirmed by our estimate of log( g ). Despite the exceptional data quality, attaining robust estimates for chemical abundances [M/H] and C/O, often employed as indicators of formation history, remains challenging. Nevertheless, the pioneering case of JWST’s data for VHS 1256 b has paved the way for future acquisitions of substellar spectra that will be systematically analyzed to directly compare the properties of these objects and correct the systematics in the models.
Published: 2024
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3. New Mass and Radius Constraints on the LHS 1140 Planets: LHS 1140 b Is either a Temperate Mini-Neptune or a Water World

Author: Charles Cadieux, Mykhaylo Plotnykov, René Doyon, Diana Valencia, Farbod Jahandar, Lisa Dang, Martin Turbet, Thomas J. Fauchez, Ryan Cloutier, Collin Cherubim, Étienne Artigau, Neil J. Cook, Billy Edwards, Tim Hallatt, Benjamin Charnay, François Bouchy, Romain Allart, Lucile Mignon, Frédérique Baron, Susana C. C. Barros, Björn Benneke, B. L. Canto Martins, Nicolas B. Cowan, J. R. De Medeiros, Xavier Delfosse, Elisa Delgado-Mena, Xavier Dumusque, David Ehrenreich, Yolanda G. C. Frensch, J. I. González Hernández, Nathan C. Hara, David Lafrenière, Gaspare Lo Curto, Lison Malo, Claudio Melo, Dany Mounzer, Vera Maria Passeger, Francesco Pepe, Anne-Sophie Poulin-Girard, Nuno C. Santos, Danuta Sosnowska, Alejandro Suárez Mascareño, Simon Thibault, Valentina Vaulato, Gregg A. Wade, and François Wildi
Subjects: Exoplanets, Habitable planets, Super Earths, M dwarf stars, Planetary interior, Astrophysics, QB460-466
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 the M4.5 host star and its small temperate exoplanets, LHS 1140 b and c. Here, we reanalyze the ESPRESSO observations of LHS 1140 with the novel line-by-line framework designed to fully exploit the radial velocity content of a stellar spectrum while being resilient to outlier measurements. The improved radial velocities, combined with updated stellar parameters, consolidate our knowledge of the mass of LHS 1140 b (5.60 ± 0.19 M _⊕ ) and LHS 1140 c (1.91 ± 0.06 M _⊕ ) with an unprecedented precision of 3%. Transits from Spitzer, HST, and TESS are jointly analyzed for the first time, allowing us to refine the planetary radii of b (1.730 ± 0.025 R _⊕ ) and c (1.272 ± 0.026 R _⊕ ). Stellar abundance measurements of refractory elements (Fe, Mg, and Si) obtained with NIRPS are used to constrain the internal structure of LHS 1140 b. This planet is unlikely to be a rocky super-Earth, as previously reported, but rather a mini-Neptune with a ∼0.1% H/He envelope by mass or a water world with a water-mass fraction between 9% and 19%, depending on the atmospheric composition and relative abundance of Fe and Mg. While the mini-Neptune case would not be habitable, a water-abundant LHS 1140 b potentially has habitable surface conditions according to 3D global climate models, suggesting liquid water at the substellar point for atmospheres with relatively low CO _2 concentration, from Earth-like to a few bars.
Published: 2024
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4. Co-evolution of primitive methane-cycling ecosystems and early Earth’s atmosphere and climate

Author: Boris Sauterey, Benjamin Charnay, Antonin Affholder, Stéphane Mazevet, and Régis Ferrière
Subjects: Science
Abstract: Biology can profoundly influence the planet’s climate, but over Earth’s long history these effects are poorly constrained. Here the authors show that on early Earth, the evolution of microbes producing and consuming methane likely controlled warming and glacial events, and thus Earth’s habitability
Published: 2020
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5. Characterization and modelling of exoplanetary atmospheres

Author: Benjamin Charnay and Pierre Drossart
Subjects: General Physics and Astronomy
Published: 2023

6. Early Mars habitability and global cooling by H2-based methanogens

Author: Boris Sauterey, Benjamin Charnay, Antonin Affholder, Stéphane Mazevet, Régis Ferrière, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université Paris Cité (UPCité), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur (OCA), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), [SDU]Sciences of the Universe [physics], FOS: Biological sciences, Populations and Evolution (q-bio.PE), FOS: Physical sciences, Astronomy and Astrophysics, Quantitative Biology - Populations and Evolution, Astrophysics - Earth and Planetary Astrophysics
Abstract: International audience; During the Noachian, Mars' crust may have provided a favourable environment for microbial life1,2. The porous brine-saturated regolith3-5 would have created a physical space sheltered from ultraviolet and cosmic radiation and provided a solvent, whereas the below-ground temperature2 and diffusion6,7 of a dense, reduced atmosphere8,9 may have supported simple microbial organisms that consumed H2 and CO2 as energy and carbon sources and produced methane as a waste. On Earth, hydrogenotrophic methanogenesis was among the earliest metabolisms10,11, but its viability on early Mars has never been quantitatively evaluated. Here we present a probabilistic assessment of Mars' Noachian habitability to H2-based methanogens and quantify their biological feedback on Mars' atmosphere and climate. We find that subsurface habitability was very likely, and limited mainly by the extent of surface ice coverage. Biomass productivity could have been as high as in the early Earth's ocean. However, the predicted atmospheric composition shift caused by methanogenesis would have triggered a global cooling event, ending potential early warm conditions, compromising surface habitability and forcing the biosphere deep into the Martian crust. Spatial projections of our predictions point to lowland sites at low-to-medium latitudes as good candidates to uncover traces of this early life at or near the surface.
Published: 2022

7. Methane as a dominant absorber in the habitable-zone sub-Neptune K2-18 b

Author: Bruno Bézard, Benjamin Charnay, Doriann Blain, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, Physics::Atmospheric and Oceanic Physics, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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-dwarf star. The detection is based on an absorption feature seen at 1.4 $\mu$m in observations of the transiting exoplanet with the Hubble Space Telescope/Wide Field Camera 3. We have simulated the mean temperature structure and composition of K2-18b using a radiative-convective equilibrium model and we present here the corresponding transit spectroscopy calculations. We argue that the reported absorption is most likely due to methane, a gas expected to be abundant in the hydrogen-helium atmosphere of cold sub-Neptunes. More generally, we show that the 1.4-$\mu$m absorption seen in transit spectra is not diagnostic of the presence of water vapour for sub-Neptunes having an effective temperature less than 600 K and that water vapour dominates over methane at this wavelength only at larger temperatures., Comment: This preprint has not undergone any post-submission improvements or corrections. The Version of Record of this article is published in Nature Astronomy (Matters Arising), and is available online at https://www.nature.com/articles/s41550-022-01678-z
Published: 2022

8. Rapid Prototyping of Lab-scale Electrolysis Cells Using Stereolithography and Electroless Plating

Author: Gage Wright, Benjamin Charnay, Joshua Rabinowitz, Ruperto Mariano, and Matthew Kanan
Abstract: Electrolysis research is typically conducted using commercially available cells with standard designs that are difficult to modify or custom-machined parts that are time-consuming to produce. Herein, we describe a method to rapidly produce lab-scale electrolysis cells that uses high-resolution, high-fidelity stereolithography 3D printing combined with electroless metal plating. Cells prepared by the printing/electroless plating method were compared to the same cells machined in Ti for CO electrolysis experiments. The printed cells showed very similar performance to the machined cells across a wide current density range (up to 250 mA cm-2) and demonstrated 24 h of stable operation in a zero-gap configuration. This work demonstrates the ability to prototype electrochemical cell designs in a fraction of the time required using conventional machining.
Published: 2023

9. Dynamics of the Great Oxidation Event from a 3D photochemical–climate model

Author: Franck Selsis, Adam Yassin Jaziri, Benjamin Charnay, Franck Lefèvre, Jérémy Leconte, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), and Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Chemical Physics (physics.chem-ph), Global and Planetary Change, Atmospheric circulation, Stratigraphy, Great Oxygenation Event, FOS: Physical sciences, Paleontology, Photochemistry, Methane, Huronian glaciation, Atmosphere, Physics - Atmospheric and Oceanic Physics, chemistry.chemical_compound, chemistry, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Physics - Chemical Physics, Atmospheric and Oceanic Physics (physics.ao-ph), Ozone layer, Atmospheric instability, Environmental science, Climate model, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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 (GOE). This rapid transition may be related to an atmospheric instability caused by the formation of the ozone layer. Previous works were all based on 1D photochemical models. Here, we revisit the GOE with a 3D photochemical-climate model to investigate the possible impact of the atmospheric circulation and the coupling between the climate and the dynamics of the oxidation. We show that the diurnal, seasonal and transport variations do not bring significant changes compared to 1D models. Nevertheless, we highlight a temperature dependence for atmospheric photochemical losses. A cooling during the late Archean could then have favored the triggering of the oxygenation. In addition, we show that the Huronian glaciations, which took place during the GOE, could have introduced a fluctuation in the evolution of the oxygen level. Finally, we show that the oxygen overshoot which is expected to have occurred just after the GOE, was likely accompanied by a methane overshoot. Such high methane concentrations could have had climatic consequences and could have played a role in the dynamics of the Huronian glaciations.
Published: 2022

10. Formation of secondary atmospheres on terrestrial planets by late disk accretion

Author: Jeanne Davoult, Quentin Kral, Benjamin Charnay, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: Planetesimal, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Protoplanetary disk, 01 natural sciences, Astrobiology, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Physics, Secondary atmosphere, Astronomy and Astrophysics, Planetary system, Photoevaporation, Accretion (astrophysics), 13. Climate action, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: 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 gas disks, mainly composed of CO, carbon, and oxygen seem to be ubiquitous in systems with planetesimal belts (similar to our Kuiper belt), and can last for hundreds of millions of years. Planets orbiting in these gas disks will accrete a large quantity of gas that will transform their primordial atmospheres into new secondary atmospheres with compositions similar to that of the parent gas disk. Here, we quantify how large a secondary atmosphere can be created for a variety of observed gas disks and for a wide range of planet types. We find that gas accretion in this late phase is very significant and an Earth's atmospheric mass of gas is readily accreted on terrestrial planets in very tenuous gas disks. In slightly more massive disks, we show that massive CO atmospheres can be accreted, forming planets with up to sub-Neptune-like pressures. Our new results demonstrate that new secondary atmospheres with high metallicities and high C/O ratios will be created in these late gas disks, resetting their primordial compositions inherited from the protoplanetary disk phase, and providing a new birth to planets that lost their atmosphere to photoevaporation or giant impacts. We therefore propose a new paradigm for the formation of atmospheres on low-mass planets, which can be tested with future observations (JWST, ELT, ARIEL). We also show that this late accretion would show a very clear signature in Sub-Neptunes or cold exo-Jupiters. Finally, we find that accretion creates cavities in late gas disks, which could be used as a new planet detection method, for low mass planets a few au to a few tens of au from their host stars., Paper accepted and now published in Nature Astronomy. See the published version here: https://www.nature.com/articles/s41550-020-1050-2
Published: 2020

11. A survey of exoplanet phase curves with Ariel

Author: Benjamin Charnay, Nicolas B. Cowan, Billy Edwards, Enzo Pascale, Jake Taylor, Olivier Demangeon, Lorenzo V. Mugnai, Laura Kreidberg, Robert T. Zellem, Carole A. Haswell, João M. Mendonça, Giuseppe Morello, Pascal Tremblin, Giovanna Tinetti, Taylor J. Bell, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), National Space Institute [Lyngby] (DTU Space), Danmarks Tekniske Universitet = Technical University of Denmark (DTU), Max Planck Institute for Astronomy (MPIA), Department of Physics [McGill University], McGill University = Université McGill [Montréal, Canada], Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford, Instituto de Astrofísica e Ciências do Espaço. Universidade do Porto, University College of London [London] (UCL), The Open University [Milton Keynes] (OU), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Phase (waves), [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Ariel space mission, atmospheres, exoplanets, phase curves, Phase curve, 01 natural sciences, Exoplanet, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Thermal, Astrophysics::Earth and Planetary Astrophysics, Atmospheric dynamics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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 exoplanet phase curves with Ariel. We define science questions, requirements and a list of potential targets. We also estimate the precision of phase curve reconstruction and atmospheric retrieval using simulated phase curves. Based on this work, we found that full-orbit phase variations for 35-40 exoplanets could be observed during the 3.5-yr mission. This statistical sample would provide key constraints on atmospheric dynamics, composition, thermal structure and clouds of warm exoplanets, complementary to the scientific yield from spectroscopic transits/eclipses measurements., 27 pages, 10 figures, accepted for publication in Experimental Astronomy, Ariel Special Issue
Published: 2022

12. Gravitational atmospheric tides as a probe of Titan's interior: Application to Dragonfly

Author: Ralph D. Lorenz, Gabriel Tobie, Benjamin Charnay, Sébastien Lebonnois, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: Physics, 010308 nuclear & particles physics, Atmospheric tide, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, Context (language use), Astrophysics, Atmospheric sciences, Surface pressure, 01 natural sciences, Atmosphere, Troposphere, symbols.namesake, Heat flux, 13. Climate action, Space and Planetary Science, Saturn, 0103 physical sciences, symbols, Titan (rocket family), 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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 troposphere. The future Dragonfly mission could analyse this exotic meteorological phenomenon. Aims: We analyse the effect of Saturn's tides on Titan's atmosphere and interior to determine how pressure measurements by Dragonfly could constrain Titan's interior. Methods: We model atmospheric tides with analytical calculations and with a 3D Global Climate Model (the IPSL-Titan GCM), including the tidal response of the interior. Results: We predict that the Love numbers of Titan's interior should verify 1 + Re(k2 - h2) ~ 0.02-0.1 and Im(k2 - h2) < 0.04. The deformation of Titan's interior should therefore strongly weaken gravitational atmospheric tides, yielding a residual surface pressure amplitude of only ~ 5 Pa, with a phase shift of 5-20 hours. Tidal winds are very weak, of the order of 3*10^-4 m/s in the lower troposphere. Finally, constraints from Dragonfly data may permit the real and the imaginary parts of k2 - h2 to be estimated with a precision of ~0.01-0.03. Conclusions: Measurements of pressure variations by Dragonfly over the whole mission could give valuable constraints on the thickness of Titan's ice shell, and via geophysical models, its heat flux and the density of Titan's internal ocean., Comment: Accepted for publication in A&A. 10 pages, 8 figures, 1 table
Published: 2021

13. CAMEMBERT: A Mini-Neptunes General Circulation Model Intercomparison, Protocol Version 1.0.A CUISINES Model Intercomparison Project

Author: Duncan A. Christie, Elspeth K. H. Lee, Hamish Innes, Pascal A. Noti, Benjamin Charnay, Thomas J. Fauchez, Nathan J. Mayne, Russell Deitrick, Feng Ding, Jennifer J. Greco, Mark Hammond, Isaac Malsky, Avi Mandell, Emily Rauscher, Michael T. Roman, Denis E. Sergeev, Linda Sohl, Maria E. Steinrueck, Martin Turbet, Eric T. Wolf, Maria Zamyatina, and Ludmila Carone
Subjects: Geophysics, 530 Physics, Space and Planetary Science, 520 Astronomy, Earth and Planetary Sciences (miscellaneous), Astronomy and Astrophysics, 500 Science
Abstract: With an increased focus on the observing and modeling of mini-Neptunes, there comes a need to better understand the tools we use to model their atmospheres. In this Paper, we present the protocol for the Comparing Atmospheric Models of Extrasolar Mini-Neptunes Building and Envisioning Retrievals and Transits, CAMEMBERT, project, an intercomparison of general circulation models (GCMs) used by the exoplanetary science community to simulate the atmospheres of mini-Neptunes. We focus on two targets well studied both observationally and theoretically with planned JWST cycle 1 observations: the warm GJ 1214b and the cooler K2-18b. For each target, we consider a temperature-forced case, a clear sky dual-gray radiative transfer case, and a clear sky multiband radiative transfer case, covering a range of complexities and configurations where we know differences exist between GCMs in the literature. This Paper presents all the details necessary to participate in the intercomparison, with the intention of presenting the results in future papers. Currently, there are eight GCMs participating (ExoCAM, Exo-FMS, FMS PCM, Generic PCM, MITgcm, RM-GCM, THOR, and the Unified Model), and membership in the project remains open. Those interested in participating are invited to contact the authors.
Published: 2022

14. Ariel: Enabling planetary science across light-years

Author: Giovanna Tinetti, Paul Eccleston, Carole Haswell, Pierre-Olivier Lagage, Jérémy Leconte, Theresa Lüftinger, Giusi Micela, Michel Min, Göran Pilbratt, Ludovic Puig, Mark Swain, Leonardo Testi, Diego Turrini, Bart Vandenbussche, Maria Rosa Zapatero Osorio, Anna Aret, Jean-Philippe Beaulieu, Buchhave, Lars A., Martin Ferus, Matt Griffin, Manuel Guedel, Paul Hartogh, Pedro Machado, Giuseppe Malaguti, Enric Pallé, Mirek Rataj, Tom Ray, Ignasi Ribas, Robert Szabó, Jonathan Tan, Stephanie Werner, Francesco Ratti, Carsten Scharmberg, Jean-Christophe Salvignol, Nathalie Boudin, Jean-Philippe Halain, Martin Haag, Pierre-Elie Crouzet, Ralf Kohley, Kate Symonds, Florian Renk, Andrew Caldwell, Manuel Abreu, Gustavo Alonso, Jerome Amiaux, Michel Berthé, Georgia Bishop, Neil Bowles, Manuel Carmona, Deirdre Coffey, Josep Colomé, Martin Crook, Lucile Désjonqueres, Díaz, José J., Rachel Drummond, Mauro Focardi, Gómez, Jose M., Warren Holmes, Matthijs Krijger, Zsolt Kovacs, Tom Hunt, Richardo Machado, Gianluca Morgante, Marc Ollivier, Roland Ottensamer, Emanuele Pace, Teresa Pagano, Enzo Pascale, Chris Pearson, Søren Møller Pedersen, Moshe Pniel, Stéphane Roose, Giorgio Savini, Richard Stamper, Peter Szirovicza, Janos Szoke, Ian Tosh, Francesc Vilardell, Joanna Barstow, Luca Borsato, Sarah Casewell, Quentin Changeat, Benjamin Charnay, Svatopluk Civiš, Vincent Coudé du Foresto, Athena Coustenis, Nicolas Cowan, Camilla Danielski, Olivier Demangeon, Pierre Drossart, Edwards, Billy N., Gabriella Gilli, Therese Encrenaz, Csaba Kiss, Anastasia Kokori, Masahiro Ikoma, Juan Carlos Morales, Joao Mendonca, Andrea Moneti, Lorenzo Mugnai, Antonio García Muñoz, Ravit Helled, Mihkel Kama, Yamila Miguel, Nikos Nikolaou, Isabella Pagano, Olja Panic, Miriam Rengel, Hans Rickman, Marco Rocchetto, Subhajit Sarkar, Franck Selsis, Jonathan Tennyson, Angelos Tsiaras, Olivia Venot, Krisztián Vida, Waldmann, Ingo P., Sergey Yurchenko, Gyula Szabó, Rob Zellem, Ahmed Al-Refaie, Javier Perez Alvarez, Lara Anisman, Axel Arhancet, Jaume Ateca, Robin Baeyens, Barnes, John R., Taylor Bell, Serena Benatti, Katia Biazzo, Maria Błęcka, Aldo Stefano Bonomo, José Bosch, Diego Bossini, Jeremy Bourgalais, Daniele Brienza, Anna Brucalassi, Giovanni Bruno, Hamish Caines, Simon Calcutt, Tiago Campante, Rodolfo Canestrari, Nick Cann, Giada Casali, Albert Casas, Giuseppe Cassone, Christophe Cara, Ludmila Carone, Nathalie Carrasco, Paolo Chioetto, Fausto Cortecchia, Markus Czupalla, Chubb, Katy L., Angela Ciaravella, Antonio Claret, Riccardo Claudi, Claudio Codella, Maya Garcia Comas, Gianluca Cracchiolo, Patricio Cubillos, Vania Da Peppo, Leen Decin, Clemence Dejabrun, Elisa Delgado-Mena, Anna Di Giorgio, Emiliano Diolaiti, Caroline Dorn, Vanessa Doublier, Eric Doumayrou, Georgina Dransfield, Luc Dumaye, Emma Dunford, Antonio Jimenez Escobar, Vincent Van Eylen, Maria Farina, Davide Fedele, Alejandro Fernández, Benjamin Fleury, Sergio Fonte, Jean Fontignie, Luca Fossati, Bernd Funke, Camille Galy, Zoltán Garai, Andrés García, Alberto García-Rigo, Antonio Garufi, Giuseppe Germano Sacco, Paolo Giacobbe, Alejandro Gómez, Arturo Gonzalez, Francisco Gonzalez-Galindo, Davide Grassi, Caitlin Griffith, Mario Giuseppe Guarcello, Audrey Goujon, Amélie Gressier, Aleksandra Grzegorczyk, Tristan Guillot, Gloria Guilluy, Peter Hargrave, Marie-Laure Hellin, Enrique Herrero, Matt Hills, Benoit Horeau, Yuichi Ito, Niels Christian Jessen, Petr Kabath, Szilárd Kálmán, Yui Kawashima, Tadahiro Kimura, Antonín Knížek, Laura Kreidberg, Ronald Kruid, Kruijssen, Diederik J. M., Petr Kubelík, Luisa Lara, Sebastien Lebonnois, David Lee, Maxence Lefevre, Tim Lichtenberg, Daniele Locci, Matteo Lombini, Alejandro Sanchez Lopez, Andrea Lorenzani, Ryan MacDonald, Laura Magrini, Jesus Maldonado, Emmanuel Marcq, Alessandra Migliorini, Darius Modirrousta-Galian, Karan Molaverdikhani, Sergio Molinari, Paul Mollière, Vincent Moreau, Giuseppe Morello, Gilles Morinaud, Mario Morvan, Moses, Julianne I., Salima Mouzali, Nariman Nakhjiri, Luca Naponiello, Norio Narita, Valerio Nascimbeni, Athanasia Nikolaou, Vladimiro Noce, Fabrizio Oliva, Pietro Palladino, Andreas Papageorgiou, Vivien Parmentier, Giovanni Peres, Javier Pérez, Santiago Perez-Hoyos, Manuel Perger, Cesare Cecchi Pestellini, Antonino Petralia, Anne Philippon, Arianna Piccialli, Marco Pignatari, Giampaolo Piotto, Linda Podio, Gianluca Polenta, Giampaolo Preti, Theodor Pribulla, Manuel Lopez Puertas, Monica Rainer, Jean-Michel Reess, Paul Rimmer, Séverine Robert, Albert Rosich, Loic Rossi, Duncan Rust, Ayman Saleh, Nicoletta Sanna, Eugenio Schisano, Laura Schreiber, Victor Schwartz, Antonio Scippa, Bálint Seli, Sho Shibata, Caroline Simpson, Oliver Shorttle, Skaf, N., Konrad Skup, Mateusz Sobiecki, Sergio Sousa, Alessandro Sozzetti, Judit Šponer, Lukas Steiger, Paolo Tanga, Paul Tackley, Jake Taylor, Matthias Tecza, Luca Terenzi, Pascal Tremblin, Andrea Tozzi, Amaury Triaud, Loïc Trompet, Shang-Min Tsai, Maria Tsantaki, Diana Valencia, Ann Carine Vandaele, Mathieu Van der Swaelmen, Adibekyan Vardan, Gautam Vasisht, Allona Vazan, Ciro Del Vecchio, Dave Waltham, Piotr Wawer, Thomas Widemann, Paulina Wolkenberg, Gordon Hou Yip, Yuk Yung, Mantas Zilinskas, Tiziano Zingales, Paola Zuppella, University College of London [London] (UCL), Space Science and Technology Department [Didcot] (RAL Space), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC), Université de Bordeaux (UB), Agence Spatiale Européenne = European Space Agency (ESA), SRON Netherlands Institute for Space Research (SRON), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Bologna (OABO), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), European Space Agency, Agence Spatiale Européenne (ESA), European Space Agency (ESA), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Giovanna Tinetti, Paul Eccleston, Carole Haswell, Pierre-Olivier Lagage, Jérémy Leconte, Theresa Lüftinger, Giusi Micela, Michel Min, Göran Pilbratt, Ludovic Puig, Mark Swain, Leonardo Testi, Diego Turrini, Bart Vandenbussche, Maria Rosa Zapatero Osorio, Anna Aret, Jean-Philippe Beaulieu, Lars Buchhave, Martin Feru, Matt Griffin, Manuel Guedel, Paul Hartogh, Pedro Machado, Giuseppe Malaguti, Enric Pallé, Mirek Rataj, Tom Ray, Ignasi Riba, Robert Szabó, Jonathan Tan, Stephanie Werner, Francesco Ratti, Carsten Scharmberg, Jean-Christophe Salvignol, Nathalie Boudin, Jean-Philippe Halain, Martin Haag, Pierre-Elie Crouzet, Ralf Kohley, Kate Symond, Florian Renk, Andrew Caldwell, Manuel Abreu, Gustavo Alonso, Jerome Amiaux, Michel Berthé, Georgia Bishop, Neil Bowle, Manuel Carmona, Deirdre Coffey, Josep Colomé, Martin Crook, Lucile Désjonquere, José J. Díaz, Rachel Drummond, Mauro Focardi, Jose M. Gómez, Warren Holme, Matthijs Krijger, Zsolt Kovac, Tom Hunt, Richardo Machado, Gianluca Morgante, Marc Ollivier, Roland Ottensamer, Emanuele Pace, Teresa Pagano, Enzo Pascale, Chris Pearson, Søren Møller Pedersen, Moshe Pniel, Stéphane Roose, Giorgio Savini, Richard Stamper, Peter Szirovicza, Janos Szoke, Ian Tosh, Francesc Vilardell, Joanna Barstow, Luca Borsato, Sarah Casewell, Quentin Changeat, Benjamin Charnay, Svatopluk Civiš, Vincent Coudé du Foresto, Athena Cousteni, Nicolas Cowan, Camilla Danielski, Olivier Demangeon, Pierre Drossart, Billy N. Edward, Gabriella Gilli, Therese Encrenaz, Csaba Ki, Anastasia Kokori, Masahiro Ikoma, Juan Carlos Morale, João Mendonça, Andrea Moneti, Lorenzo Mugnai, Antonio García Muñoz, Ravit Helled, Mihkel Kama, Yamila Miguel, Nikos Nikolaou, Isabella Pagano, Olja Panic, Miriam Rengel, Hans Rickman, Marco Rocchetto, Subhajit Sarkar, Franck Selsi, Jonathan Tennyson, Angelos Tsiara, Olivia Venot, Krisztián Vida, Ingo P. Waldmann, Sergey Yurchenko, Gyula Szabó, Rob Zellem, Ahmed Al-Refaie, Javier Perez Alvarez, Lara Anisman, Axel Arhancet, Jaume Ateca, Robin Baeyen, John R. Barne, Taylor Bell, Serena Benatti, Katia Biazzo, Maria Błęcka, Aldo Stefano Bonomo, José Bosch, Diego Bossini, Jeremy Bourgalai, Daniele Brienza, Anna Brucalassi, Giovanni Bruno, Hamish Caine, Simon Calcutt, Tiago Campante, Rodolfo Canestrari, Nick Cann, Giada Casali, Albert Casa, Giuseppe Cassone, Christophe Cara, Ludmila Carone, Nathalie Carrasco, Paolo Chioetto, Fausto Cortecchia, Markus Czupalla, Katy L. Chubb, Angela Ciaravella, Antonio Claret, Riccardo Claudi, Claudio Codella, Maya Garcia Coma, Gianluca Cracchiolo, Patricio Cubillo, Vania Da Peppo, Leen Decin, Clemence Dejabrun, Elisa Delgado-Mena, Anna Di Giorgio, Emiliano Diolaiti, Caroline Dorn, Vanessa Doublier, Eric Doumayrou, Georgina Dransfield, Luc Dumaye, Emma Dunford, Antonio Jimenez Escobar, Vincent Van Eylen, Maria Farina, Davide Fedele, Alejandro Fernández, Benjamin Fleury, Sergio Fonte, Jean Fontignie, Luca Fossati, Bernd Funke, Camille Galy, Zoltán Garai, Andrés García, Alberto García-Rigo, Antonio Garufi, Giuseppe Germano Sacco, Paolo Giacobbe, Alejandro Gómez, Arturo Gonzalez, Francisco Gonzalez-Galindo, Davide Grassi, Caitlin Griffith, Mario Giuseppe Guarcello, Audrey Goujon, Amélie Gressier, Aleksandra Grzegorczyk, Tristan Guillot, Gloria Guilluy, Peter Hargrave, Marie-Laure Hellin, Enrique Herrero, Matt Hill, Benoit Horeau, Yuichi Ito, Niels Christian Jessen, Petr Kabath, Szilárd Kálmán, Yui Kawashima, Tadahiro Kimura, Antonín Knížek, Laura Kreidberg, Ronald Kruid, Diederik J. M. Kruijssen, Petr Kubelík, Luisa Lara, Sebastien Lebonnoi, David Lee, Maxence Lefevre, Tim Lichtenberg, Daniele Locci, Matteo Lombini, Alejandro Sanchez Lopez, Andrea Lorenzani, Ryan MacDonald, Laura Magrini, Jesus Maldonado, Emmanuel Marcq, Alessandra Migliorini, Darius Modirrousta-Galian, Karan Molaverdikhani, Sergio Molinari, Paul Mollière, Vincent Moreau, Giuseppe Morello, Gilles Morinaud, Mario Morvan, Julianne I. Mose, Salima Mouzali, Nariman Nakhjiri, Luca Naponiello, Norio Narita, Valerio Nascimbeni, Athanasia Nikolaou, Vladimiro Noce, Fabrizio Oliva, Pietro Palladino, Andreas Papageorgiou, Vivien Parmentier, Giovanni Pere, Javier Pérez, Santiago Perez-Hoyo, Manuel Perger, Cesare Cecchi Pestellini, Antonino Petralia, Anne Philippon, Arianna Piccialli, Marco Pignatari, Giampaolo Piotto, Linda Podio, Gianluca Polenta, Giampaolo Preti, Theodor Pribulla, Manuel Lopez Puerta, Monica Rainer, Jean-Michel Ree, Paul Rimmer, Séverine Robert, Albert Rosich, Loic Rossi, Duncan Rust, Ayman Saleh, Nicoletta Sanna, Eugenio Schisano, Laura Schreiber, Victor Schwartz, Antonio Scippa, Bálint Seli, Sho Shibata, Caroline Simpson, Oliver Shorttle, N. Skaf, Konrad Skup, Mateusz Sobiecki, Sergio Sousa, Alessandro Sozzetti, Judit Šponer, Lukas Steiger, Paolo Tanga, Paul Tackley, Jake Taylor, Matthias Tecza, Luca Terenzi, Pascal Tremblin, Andrea Tozzi, Amaury Triaud, Loïc Trompet, Shang-Min Tsai, Maria Tsantaki, Diana Valencia, Ann Carine Vandaele, Mathieu Van der Swaelmen, Adibekyan Vardan, Gautam Vasisht, Allona Vazan, Ciro Del Vecchio, Dave Waltham, Piotr Wawer, Thomas Widemann, Paulina Wolkenberg, Gordon Hou Yip, Yuk Yung, Mantas Zilinska, Tiziano Zingale, Paola Zuppella, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), and Cardon, Catherine
Subjects: [SDU] Sciences of the Universe [physics], Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR.IM] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Settore FIS/05 - Astronomia E Astrofisica, [SDU]Sciences of the Universe [physics], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics - Instrumentation and Methods for Astrophysic, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics - Earth and Planetary Astrophysics, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]
Abstract: 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. 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 visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 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 payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution., Comment: Ariel Definition Study Report, 147 pages. Reviewed by ESA Science Advisory Structure in November 2020. Original document available at: https://www.cosmos.esa.int/documents/1783156/3267291/Ariel_RedBook_Nov2020.pdf/
Published: 2021
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15. HST WFC3 G141 data analysis: exploring the transition from Super-Earth to Sub-Neptune

Author: Emmanuel Marcq, Amélie Gressier, Jean-Philippe Beaulieu, Benjamin Charnay, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: Physics, Super-Earth, 13. Climate action, Neptune, [SDU]Sciences of the Universe [physics], Astronomy, ComputingMilieux_MISCELLANEOUS
Abstract: Exoplanets with size between the Earth and Neptune (1-4R⊕) do not have any equivalent in our Solar System and remain challenging to characterize. Yet, there are ubiquitous in the Galaxy and Fulton et al. (2017) showed that their distribution (number of planets per star vs radius) is bimodal highlighting a gap in the number of planets around 1.7R⊕. Planets with a radius below 1.7R⊕ are thought to be mostly rocky planets, and called Super-Earth, above this limit planets are most likely made of gas and called Sub-Neptune. We made use of the available data from the Hubble Space Telescope in Near-Infrared (HST WFC3 G141) and gathered 18 transmission spectra of planets with size below 6 R⊕ to study the transition between rocky and gaseous planets. First, we used TauREx3 (Al-Refaie et al. 2019), a Bayesian retrieval code, to rule out atmospheric scenarios. We proved that a primary clear atmosphere dominated by Hydrogen and Helium is rejected with more than 3σ for a large majority of planets in the sample. Then, we measured the amplitude of the spectra in the water absorption band (around 1.4μm) and compared observational values to simulated ones using a self-consistent modeling code ExoREM (Baudino et al. 2015; Charnay et al. 2018). We explored the connection between the water absorption amplitudes and the temperature by setting the stellar and planetary parameters to those of HD 3167 c (2.7 R⊕, 8.33 M⊕) and trying different metallicities (1, 10, 100 and 1000 x solar), cloud compositions and temperatures (300-1200K).
Published: 2021

16. Is the Pale Blue Dot Unique? Optimized Photometric Bands for Identifying Earth-Like Exoplanets

Author: Joshua Krissansen-Totton, Edward W Schwieterman, Benjamin Charnay, Giada Arney, Tyler D Robinson, Victoria Meadows, and David C Catling
Subjects: Lunar and Planetary Science and Exploration
Abstract: 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 spectroscopy, but less consideration has been given to the usefulness of planet colors. Here, we investigate whether potentially Earth-like exoplanets could be identified using UV-visible-to-NIR wavelength broadband photometry (350–1000 nm). Specifically, we calculate optimal photometric bins for identifying an exo-Earth and distinguishing it from uninhabitable planets including both Solar System objects and model exoplanets. The color of some hypothetical exoplanets—particularly icy terrestrial worlds with thick atmospheres—is similar to Earth's because of Rayleigh scattering in the blue region of the spectrum. Nevertheless, subtle features in Earth's reflectance spectrum appear to be unique. In particular, Earth's reflectance spectrum has a “U-shape” unlike all our hypothetical, uninhabitable planets. This shape is partly biogenic because O2-rich, oxidizing air is transparent to sunlight, allowing prominent Rayleigh scattering, while ozone absorbs visible light, creating the bottom of the “U.” Whether such uniqueness has practical utility depends on observational noise. If observations are photon limited or dominated by astrophysical sources (zodiacal light or imperfect starlight suppression), then the use of broadband visible wavelength photometry to identify Earth twins has little practical advantage over obtaining detailed spectra. However, if observations are dominated by dark current, then optimized photometry could greatly assist preliminary characterization. We also calculate the optimal photometric bins for identifying extrasolar Archean Earths, and find that the Archean Earth is more difficult to unambiguously identify than a modern Earth twin.
Published: 2016
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17. ARES V: No evidence for molecular absorption in the HST WFC3 spectrum of GJ 1132 b

Author: Jeroen Bouwman, Benjamin Charnay, Quentin Changeat, William Pluriel, Pierre Drossart, Amélie Gressier, Niall Whiteford, Tiziano Zingales, Mario Morvan, Ahmed Al-Refaie, Jean-Philippe Beaulieu, Sam Wright, Michelle Fabienne Bieger, Jérémy Leconte, Nour Skaf, Mathilde Poveda, Kai Hou Yip, Giuseppe Morello, Darius Modirrousta-Galian, Ingo Waldmann, Billy Edwards, Doriann Blain, Yassin Jaziri, Flavien Kiefer, Robin Baeyens, Gloria Guilluy, Olivia Venot, Lorenzo V. Mugnai, Dipartimento di Fisica [Roma La Sapienza], Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), INAF - Osservatorio Astronomico di Palermo (OAPa), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Chimica [Palermo] (DiFC), Università degli studi di Palermo - University of Palermo, Department of Physics and Astronomy [UCL London], University College of London [London] (UCL), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Instituto de Astrofisica de Canarias (IAC), Institute of Astronomy [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), College of Engineering, Mathematics and Physical Sciences [Exeter] (EMPS), University of Exeter, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica [Torino], Università degli studi di Torino = University of Turin (UNITO), INAF - Osservatorio Astrofisico di Torino (OATo), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Subaru Telescope, National Astronomical Observatory of Japan (NAOJ), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Centre for Exoplanet Science, School of Physical Sciences [Hobart], University of Tasmania [Hobart, Australia] (UTAS), European Union’s Horizon 2020 research and innovation program under the Marie SkłodowskaCurie grant agreement No. 895525., ANR-16-CE31-0005,e-PYTHEAS,Etude des hydrocarbures en émission et absorption dasn les exoplanètes à haute température(2016), European Project: 776403,EXOPLANET, European Project: 757858,ATMO, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Università degli studi di Torino (UNITO), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: 010504 meteorology & atmospheric sciences, HD 3167C, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], STELLAR ATMOSPHERE MODELS, FOS: Physical sciences, SUPER-EARTH, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astronomy & Astrophysics, 01 natural sciences, Spectral line, 55 CNC E, Atmosphere, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, TRANSMISSION SPECTRUM, KEPLER PLANETS, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, PLANETARY SYSTEM, HOT, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Science & Technology, Secondary atmosphere, EXOMOL LINE LISTS, ERROR-CORRECTION, James Webb Space Telescope, Astronomy and Astrophysics, Exoplanet, Grism, 13. Climate action, Space and Planetary Science, Exoplanet atmospheres, Astronomy data analysis, Hubble Space Telescope, Exoplanets, Physical Sciences, Astrophysics::Earth and Planetary Astrophysics, Wide Field Camera 3, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present a study on the spatially scanned spectroscopic observations of the transit of GJ 1132 b, a warm ($\sim$500 K) Super-Earth (1.13 R$_\oplus$) that was obtained with the G141 grism (1.125 - 1.650 $\mu$m) of the Wide Field Camera 3 (WFC3) onboard the Hubble Space Telescope. We used the publicly available Iraclis pipeline to extract the planetary transmission spectra from the five visits and produce a precise transmission spectrum. We analysed the spectrum using the TauREx3 atmospheric retrieval code with which we show that the measurements do not contain molecular signatures in the investigated wavelength range and are best-fit with a flat-line model. Our results suggest that the planet does not have a clear primordial, hydrogen-dominated atmosphere. Instead, GJ 1132 b could have a cloudy hydrogen-dominated envelope, a very enriched secondary atmosphere, be airless, or have a tenuous atmosphere that has not been detected. Due to the narrow wavelength coverage of WFC3, these scenarios cannot be distinguished yet but the James Webb Space Telescope may be capable of detecting atmospheric features, although several observations may be required to provide useful constraints., Comment: 17 pages, 11 figures. Accepted for publication in AJ
Published: 2021

18. Formation and dynamics of water clouds on temperate sub-Neptunes: the example of K2-18b

Author: Bruno Bézard, Aurelien Falco, Jérémy Leconte, Doriann Blain, Martin Turbet, Benjamin Charnay, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Paris, Université Paris sciences et lettres (PSL), ECLIPSE 2021, Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Solar System, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Metallicity, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, 01 natural sciences, Atmosphere, Planet, 0103 physical sciences, Thermal, Cloud condensation nuclei, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, planets and satellites: atmospheres, [PHYS]Physics [physics], Astronomy and Astrophysics, Exoplanet, planets and satellites: gaseous planets, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Water vapor, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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 studies also predict the formation of water clouds at some conditions. However, such models cannot predict the cloud cover, driven by atmospheric dynamics and thermal contrasts, and thus their real impact on spectra. The main goal of this study is to understand the formation, distribution and observational consequences of water clouds on K2-18b and other temperate sub-Neptunes. We simulated the atmospheric dynamics, water cloud formation and spectra of K2-18b for H2-dominated atmosphere using a 3D GCM. We analysed the impact of atmospheric composition (with metallicity from 1*solar to 1000*solar), concentration of cloud condensation nuclei and planetary rotation rate. Assuming that K2-18b has a synchronous rotation, we show that the atmospheric circulation in the upper atmosphere essentially corresponds to a symmetric day-to-night circulation. This regime preferentially leads to cloud formation at the substellar point or at the terminator. Clouds form for metallicity >100*solar with relatively large particles. For 100-300*solar metallicity, the cloud fraction at the terminators is small with a limited impact on transit spectra. For 1000*solar metallicity, very thick clouds form at the terminator. The cloud distribution appears very sensitive to the concentration of CCN and to the planetary rotation rate. Fitting HST transit data with our simulated spectra suggests a metallicity of ~100-300*solar. In addition, we found that the cloud fraction at the terminator can be highly variable, leading to a potential variability in transit spectra. This effect could be common on cloudy exoplanets and could be detectable with multiple transit observations., Accepted for publication in A&A. 16 pages, 14 figures
Published: 2021

19. Eco-evolutionary modeling of planetary ecosystems to predict habitability and biosignatures – the cases of early Earth and Mars

Author: Stephane Mazevet, Antonin Affholder, Régis Ferrière, Boris Sauterey, Benjamin Charnay, and François Guyot
Subjects: Eco evolutionary, Habitability, Environmental science, Ecosystem, Mars Exploration Program, Early Earth, Astrobiology
Published: 2021

20. Photochemical Hazes

Author: Benjamin Charnay
Published: 2021

21. Atmospheric Retrieval for Exoplanets

Author: Benjamin Charnay
Published: 2021

22. 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)

Author: Sébastien Rodriguez, Sandrine Vinatier, Daniel Cordier, Gabriel Tobie, Richard K. Achterberg, Carrie M. Anderson, Sarah V. Badman, Jason W. Barnes, Erika L. Barth, Bruno Bézard, Nathalie Carrasco, Benjamin Charnay, Roger N. Clark, Patrice Coll, Thomas Cornet, Athena Coustenis, Isabelle Couturier-Tamburelli, Michel Dobrijevic, F. Michael Flasar, Remco de Kok, Caroline Freissinet, Marina Galand, Thomas Gautier, Wolf D. Geppert, Caitlin A. Griffith, Murthy S. Gudipati, Lina Z. Hadid, Alexander G. Hayes, Amanda R. Hendrix, Ralf Jaumann, Donald E. Jennings, Antoine Jolly, Klara Kalousova, Tommi T. Koskinen, Panayotis Lavvas, Sébastien Lebonnois, Jean-Pierre Lebreton, Alice Le Gall, Emmanuel Lellouch, Stéphane Le Mouélic, Rosaly M. C. Lopes, Juan M. Lora, Ralph D. Lorenz, Antoine Lucas, Shannon MacKenzie, Michael J. Malaska, Kathleen Mandt, Marco Mastrogiuseppe, Claire E. Newman, Conor A. Nixon, Jani Radebaugh, Scot C. Rafkin, Pascal Rannou, Ella M. Sciamma-O’Brien, Jason M. Soderblom, Anezina Solomonidou, Christophe Sotin, Katrin Stephan, Darrell Strobel, Cyril Szopa, Nicholas A. Teanby, Elizabeth P. Turtle, Véronique Vuitton, Robert A. West, Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géosciences [UMR_C 6112] (LPG), Université d'Angers (UA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, NASA Goddard Space Flight Center (GSFC), Department of Physics and Astronomy [Leicester], University of Leicester, University of Idaho [Moscow, USA], Southwest Research Institute [Boulder] (SwRI), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Planetary Science Institute [Tucson] (PSI), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physical Geography [Utrecht], Utrecht University [Utrecht], Department of Physics [Imperial College London], Imperial College London, Department of Physics [Stockholm], Stockholm University, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Cornell University [New York], Institute of Geological Sciences [Berlin], Department of Earth Sciences [Berlin], Free University of Berlin (FU)-Free University of Berlin (FU), Faculty of Mathematics and Physics [Charles University of Praha], Charles University [Prague] (CU), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Department of Earth and Planetary Sciences [New Haven], Yale University [New Haven], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Aeolis Research, Department of Geological Sciences [BYU], Brigham Young University (BYU), Space Science and Astrobiology Division at Ames, NASA Ames Research Center (ARC), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Johns Hopkins University (JHU), School of Earth Sciences [Bristol], University of Bristol [Bristol], Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), European Space Agency (ESA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPC), Université Paris sciences et lettres (PSL), Lancaster University, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPC), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National d’Études Spatiales [Paris] (CNES)
Subjects: geology, space mission concept, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Habitability, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, orbiter, 7. Clean energy, 01 natural sciences, drones, Orbiter, Poseidon, 0103 physical sciences, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 0105 earth and related environmental sciences, Drones, Earth and Planetary Astrophysics (astro-ph.EP), Atmosphere, 500 Naturwissenschaften und Mathematik::520 Astronomie::520 Astronomie und zugeordnete Wissenschaften, Astronomy and Astrophysics, Geology, FOS: Earth and related environmental sciences, habitability, lake lander, 13. Climate action, Space and Planetary Science, atmosphere, Astrophysics - Instrumentation and Methods for Astrophysics, Titan, Lake lander, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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 moon Titan. Titan, a "world with two oceans", is an organic-rich body with interior-surface-atmosphere interactions that are comparable in complexity to the Earth. Titan is also one of the few places in the Solar System with habitability potential. Titan remarkable nature was only partly revealed by the Cassini-Huygens mission and still holds mysteries requiring a complete exploration using a variety of vehicles and instruments. The proposed mission concept POSEIDON (Titan POlar Scout/orbitEr and In situ lake lander DrONe explorer) would perform joint orbital and in situ investigations of Titan. It is designed to build on and exceed the scope and scientific/technological accomplishments of Cassini-Huygens, exploring Titan in ways that were not previously possible, in particular through full close-up and in situ coverage over long periods of time. In the proposed mission architecture, POSEIDON consists of two major elements: a spacecraft with a large set of instruments that would orbit Titan, preferably in a low-eccentricity polar orbit, and a suite of in situ investigation components, i.e. a lake lander, a "heavy" drone (possibly amphibious) and/or a fleet of mini-drones, dedicated to the exploration of the polar regions. The ideal arrival time at Titan would be slightly before the next northern Spring equinox (2039), as equinoxes are the most active periods to monitor still largely unknown atmospheric and surface seasonal changes. The exploration of Titan northern latitudes with an orbiter and in situ element(s) would be highly complementary with the upcoming NASA New Frontiers Dragonfly mission that will provide in situ exploration of Titan equatorial regions in the mid-2030s., Comment: arXiv admin note: substantial text overlap with arXiv:1908.01374
Published: 2021
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23. The mass of β Pictoris c from β Pictoris b orbital motion

Author: Matthias Samland, Anne-Lise Maire, David Mouillet, Andreas Eckart, Valentin Christiaens, Julien Woillez, Sarah Blunt, K. Perraut, T. Paumard, T. Ott, Myriam Benisty, E. Nasedkin, A. Mérand, Z. Hubert, Stefan Hippler, Frank Eisenhauer, Roderick Dembet, Gilles Otten, F. H. Vincent, Pierre Léna, Jinyi Shangguan, Miriam Keppler, Ekkehard Wieprecht, G. Bourdarot, M. Houllé, Odele Straub, Alexander J. Bohn, M. Nowak, Felix Widmann, K. Ward-Duong, P. T. de Zeeuw, J.-B. Le Bouquin, Julia Stadler, T. Taro Shimizu, A. Boccaletti, David K. Sing, Ji Wang, Linda J. Tacconi, Arthur Vigan, Elodie Choquet, Jens Kammerer, Claudia Paladini, J. Rameau, R. J. García López, Xavier Haubois, E. Rickman, Guy Perrin, J. P. Berger, Wolfgang Brandner, Eric Gendron, G. Heißel, H. Bonnet, Laurent Jocou, A. Cridland, S. D. von Fellenberg, Pierre Kervella, R. Asensio-Torres, G. Rousset, O. Pfuhl, Erich Wiezorrek, M. Bonnefoy, Y. Clénet, Senol Yazici, R. Abuter, John D. Monnier, Laura Kreidberg, Paulo J. V. Garcia, Zafar Rustamkulov, Tomas Stolker, Gilles Duvert, Paul Mollière, H. Beust, Eckhard Sturm, António Amorim, Anne-Marie Lagrange, Paola Caselli, Christian Straubmeier, Th. Henning, G. Chauvin, Benjamin Charnay, Sylvestre Lacour, E. F. van Dishoeck, Jason Dexter, Stefan Gillessen, André Young, D. Lutz, V. Coudé du Foresto, R. Genzel, Feng Gao, J. H. Girard, Faustine Cantalloube, L. Rodet, Sasha Hinkley, A. Drescher, Vincent Lapeyrere, Laurent Pueyo, Matthew Horrobin, M. L. Bolzer, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), MacoPharma, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Caltech Department of Astronomy [Pasadena], California Institute of Technology (CALTECH), Departamento de Astronomía, Universidad de Chile = University of Chile [Santiago] (UCHILE), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, European Southern Observatory (ESO), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Max-Planck-Institut für Astronomie (MPIA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Service de Pathologie respiratoire et allergologie [CHU Limoges], CHU Limoges, University of Auckland [Auckland], the GRAVITY Collaboration, Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Harvard University-Smithsonian Institution, and Université de Genève = University of Geneva (UNIGE)
Subjects: Astrophysics - instrumentation and methods for astrophysics, planets and satellites: detection, 010504 meteorology & atmospheric sciences, Astrophysics, Astrophysics - Earth and planetary astrophysics, 01 natural sciences, High angular resolution, Planet, instrumentation: high angular resolution, 0103 physical sciences, Beta Pictoris, 10. No inequality, instrumentation: interferometers, 010303 astronomy & astrophysics, Instrumentation, 0105 earth and related environmental sciences, Orbital elements, Physics, Interferometers, Astronomy and Astrophysics, Astrometry, Exoplanet, Radial velocity, Detection, Space and Planetary Science, Orbital motion, Planets and satellites, Eccentricity (mathematics), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Aims.We aim to demonstrate that the presence and mass of an exoplanet can now be effectively derived from the astrometry of another exoplanet.Methods.We combined previous astrometry ofβPictoris b with a new set of observations from the GRAVITY interferometer. The orbital motion ofβPictoris b is fit using Markov chain Monte Carlo simulations in Jacobi coordinates. The inner planet,βPictoris c, was also reobserved at a separation of 96 mas, confirming the previous orbital estimations.Results.From the astrometry of planet b only, we can (i) detect the presence ofβPictoris c and (ii) constrain its mass to 10.04−3.10+4.53MJup. If one adds the astrometry ofβPictoris c, the mass is narrowed down to 9.15−1.06+1.08MJup. The inclusion of radial velocity measurements does not affect the orbital parameters significantly, but it does slightly decrease the mass estimate to 8.89−0.75+0.75MJup. With a semimajor axis of 2.68 ± 0.02 au, a period of 1221 ± 15 days, and an eccentricity of 0.32 ± 0.02, the orbital parameters ofβPictoris c are now constrained as precisely as those ofβPictoris b. The orbital configuration is compatible with a high-order mean-motion resonance (7:1). The impact of the resonance on the planets’ dynamics would then be negligible with respect to the secular perturbations, which might have played an important role in the eccentricity excitation of the outer planet.
Published: 2021

24. ARES IV: Probing the Atmospheres of the Two Warm Small Planets HD 106315c and HD 3167c with the HST/WFC3 Camera

Author: Sam Wright, Emmanuel Marcq, Adam Yassin Jaziri, Amélie Gressier, Quentin Changeat, Doriann Blain, Michelle Fabienne Bieger, Alexandre Santerne, Jérémy Leconte, Ahmed Al-Refaie, Darius Modirrousta-Galian, Alessandro Sozzetti, Tiziano Tsingales, William Pluriel, Pierre Drossart, Jean-Philippe Beaulieu, Gloria Guilluy, Kai Hou Yip, Niall Whiteford, Olivia Venot, Lorenzo V. Mugnai, Ingo Waldmann, Mario Morvan, Robin Baeyens, Flavien Kiefer, Billy Edwards, Angelos Tsiaras, Mathilde Poveda, Nour Skaf, Benjamin Charnay, Dipartimento di Fisica [Torino], Università degli studi di Torino = University of Turin (UNITO), INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Department of Physics and Astronomy [UCL London], University College of London [London] (UCL), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Palermo (OAPa), Dipartimento di Fisica e Chimica [Palermo] (DiFC), Università degli studi di Palermo - University of Palermo, Instituut voor Sterrenkunde [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), College of Engineering, Mathematics and Physical Sciences [Exeter] (EMPS), University of Exeter, Dipartimento di Fisica [Roma La Sapienza], Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Centre for Exoplanet Science, School of Physical Sciences [Hobart], University of Tasmania [Hobart, Australia] (UTAS), ANR-16-CE31-0005,e-PYTHEAS,Etude des hydrocarbures en émission et absorption dasn les exoplanètes à haute température(2016), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Università degli studi di Torino (UNITO), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Paris (UP)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)
Subjects: astronomy data analysis, Exoplanets, Exoplanet atmospheres, Hubble Space Telescope, EXOPLANET, 010504 meteorology & atmospheric sciences, Infrared, MODELS, Astrophysics, Astronomy & Astrophysics, 01 natural sciences, 7. Clean energy, Atmosphere, METHANE, Planet, Hubble space telescope, 0103 physical sciences, PHOTOMETRY, Absorption (logic), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, SPECTRUM, Science & Technology, SPECTROSCOPY, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Radius, FRAMEWORK, Exoplanet, LINE LISTS, TRANSITING PLANET, 13. Climate action, Space and Planetary Science, Physical Sciences, Wide Field Camera 3, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present an atmospheric characterization study of two medium sized planets bracketing the radius of Neptune: HD 106315 c (R$_{\rm{P}}$=4.98 $\pm$ 0.23 R$_{\oplus}$) and HD 3167 c (R$_{\rm{P}}$=2.740$_{-0.100}^{+0.106}$ R$_{\oplus}$). We analyse spatially scanned spectroscopic observations obtained with the G141 grism (1.125 - 1.650 $\mu$m) of the Wide Field Camera 3 (WFC3) onboard the Hubble Space Telescope. We use the publicly available Iraclis pipeline and TauREx3 atmospheric retrieval code and we detect water vapor in the atmosphere of both planets with an abundance of $\log_{10}[\mathrm{H_2O}]=-2.1^{+0.7}_{-1.3}$ ($\sim$5.68$\sigma$) and $\log_{10}[\mathrm{H_2O}]=-4.1^{+0.9}_{-0.9}$ ($\sim$3.17$\sigma$) for HD 106315 c and HD 3167 c, respectively. The transmission spectrum of HD 106315 c shows also a possible evidence of ammonia absorption ($\log_{10}[\mathrm {NH_3}]=-4.3^{+0.7}_{-2.0}$, $\sim$1.97$\sigma$ -even if it is not significant-), whilst carbon dioxide absorption features may be present in the atmosphere of HD 3167 c in the $\sim$1.1-1.6~$\mu$m wavelength range ($\log_{10}[\mathrm{CO_{2}}]= -2.4^{+0.7}_{-1.0}$, $\sim$3.28$\sigma$). However the CO$_2$ detection appears significant, it must be considered carefully and put into perspective. Indeed, CO$_2$ presence is not explained by 1D equilibrium chemistry models, and it could be due to possible systematics. The additional contribution of clouds, CO and CH$_4$ are discussed. HD 106315 c and HD 3167 c will be interesting targets for upcoming telescopes such as the James Webb Space Telescope (JWST) and the Atmospheric Remote-Sensing Infrared Exoplanet Large-Survey (Ariel)., Comment: Accepted for publication in AJ
Published: 2021

25. The haze of Pluto: exploring its radiative impact on the climate

Author: Tanguy Bertrand, Emmanuel Lellouch, Xi Zhang, Lora Jovanovic, Thomas Gautier, Nathalie Carrasco, Ella Sciamma-O'Brien, Francois Forget, Pascal Rannou, Benjamin Charnay, Ted Roush, and Farid Salama
Abstract: Introduction The thermal profile of Pluto’s atmosphere has been measured from ground-based observations and from the REX instrument on-board New Horizons [1,2]. From the surface to the top of the atmosphere, the profiles show a 3-km deep ~37 K cold layer above the N2 ice-covered surface, a strong positive gradient below 50 km, warming the stratosphere up to 110 K, and a 40 K negative gradient cooling the upper atmosphere to 70 K. Our objective is to study the radiative balance of Pluto’s atmosphere in 1D with a radiative-convective model, and in 3D with the full Pluto Global Climate Model (GCM), taking into account the radiative impact of haze particles. We focus on three aspects of the thermal profile with the GCM: (1) It has been suggested that the organic haze has a significant radiative impact and is responsible for the cooling of the upper atmosphere [3]. However, this has not been explored yet in details in a GCM and remains to be tested against JWST observations of Pluto’s atmosphere thermal emission. (2) The depth of the near-surface cold layer in the GCM is currently only 1 km, versus 3 km in the observations [4,5]. (3) The significant temperature gradient between the equator and the north pole tentatively indicated by recent ALMA observations (PI Lellouch) is not predicted by current models, because the long radiative timescale of Pluto’s atmosphere should prevent horizontal temperature gradients. However, by radiating in the infrared, haze particles could shorten the radiative timescale and trigger significant temperature gradients. The Pluto GCM The GCM is described in detail in [4,5]. It takes into account the sublimation and condensation cycles of N2, CH4, and CO [4], their thermal and dynamical effects, the cloud formation, the vertical turbulent mixing, molecular thermal conduction, and a detailed surface thermal model with different thermal inertia for various timescales (diurnal, seasonal). It also includes a parameterization of the formation of organic haze [6]. We use the 1D radiative-convection version of the GCM to explore the radiative impact of haze depending on the haze properties. We then use the 3D GCM to explore the effect in a climatic context, with consistent 3D predictions for haze formation and methane abundance, which are used as an input for our radiative transfer calculation. At the conference we will present the results obtained with our model for different types of haze particles (spheres, fractal aggregates) and different datasets of laboratory-generated optical constants. We will reveal if the radiative haze can solve the three mysteries mentioned in Section 1, and how it impacts Pluto’s atmosphere dynamics. Acknowledgements T.B. was supported for this research by an appointment to the National Aeronautics and Space Administration (NASA) Post-doctoral Program at the Ames Research Center administered by Universities Space Research Association (USRA) through a contract with NASA. References [1] Hinson, D. P., et al., Radio occultation measurements of Pluto’s neutral atmosphere with New Horizons, Icarus, 290, 96–111, 2017. [2] A. Dias-Oliveira et al., Pluto's atmosphere from stellar occultations in 2012 and 2013, ApJ 811, 53, 2015. [3] Zhang, X., et al, Haze heats Pluto's atmosphere yet explains its cold temperature, Nature, 2017. [4] Forget, F., et al., A post-new horizons global climate model of Pluto including the N2, CH4 and CO cycles, Icarus, 287, 54–71, 2017. [5] Bertrand, T., et al., Pluto’s Beating Heart Regulates the Atmospheric Circulation: Results From High-Resolution and Multiyear Numerical Climate Simulations. JGR: Planets, 125(2), 1–24, 2020. [6] Bertrand, T. and Forget, F.: 3D modeling of organic haze in Pluto’s atmosphere, Icarus, 287:72, 2017.
Published: 2020

26. Formation and dynamics of water clouds on K2-18 b

Author: Benjamin Charnay, Doriann Blain, Bruno Bézard, Martin Turbet, and Jérémy Leconte
Subjects: Physics, Chemical physics, Dynamics (mechanics)
Abstract: K2-18 b is a temperate sub-Neptune orbiting in the habitable zone of a nearby M star. Recent analysis of HST transit observations revealed the presence of water vapour and potentially water clouds. K2-18b is a unique opportunity to characterize the physics, chemistry and dynamics of temperate low-mass exoplanets. We present here the results of 3D atmospheric modelling of K2-18b including water clouds with radiative effects. We investigate the effects of atmospheric metallicity (from 1xsolar to 1000xsolar), the concentration of cloud condensation nuclei, microphysics and rotation rate on the distribution of water clouds. We also analyze the impact of clouds and their spatial/time variability on transmission and emission spectra. Finally, we show how future observations with JWST, ELTs and ARIEL would constrain the atmospheric composition and clouds of this planet.
Published: 2020

27. 1D atmospheric modelling of K2-18b

Author: Doriann Blain, Benjamin Charnay, and Bruno Bézard
Abstract: The atmospheric composition of exoplanets with masses between 2 and 10 M⊕ is poorly known. In that regard, the sub-Neptune K2-18b offers a valuable opportunity for the characterisation of such atmospheres under Earth-like stellar irradiation. Previous analyses of its transmission spectrum from the Kepler, Hubble and Spitzer space telescopes data using both retrieval algorithms and forward-modelling suggest the presence H2O, as well as a low amount of CH4 in a H2–He atmosphere. We present here simulations of the atmosphere of K2-18 b using Exo-REM, our self-consistent 1D atmospheric model — recently adapted for transiting, high-metallicity giant exoplanets — to study the atmosphere of K2-18b. We compared the transmission spectra computed by our model with the above-mentionned data (0.4 to 5 μm) to infer the planet atmospheric composition assuming a H2–He dominated atmosphere. We investigated the effect of irradiation, eddy diffusion coefficient, internal source, clouds, C/O ratio and metallicity on the atmospheric structure and transit spectrum. We will put an emphasis of the relative contributions of the various absorbers to the transmission spectrum. We will show that our simulations favor atmospheric metallicities from 100 to 200 times solar. We will also discuss the possibility of a CH4-depleted atmosphere and of liquid H2O cloud formation.
Published: 2020

28. Direct confirmation of the radial-velocity planet β Pictoris c

Author: Benjamin Charnay, Feng Gao, Antoine Mérand, L. Rodet, H. Bonnet, Tyler Gardner, Jean-Phillipe Berger, E. F. van Dishoeck, Anthony Boccaletti, Stefan Gillessen, Felix Widmann, Eric Gendron, Hervé Beust, Karine Perraut, Wolfgang Brandner, A. Cridland, J. Rameau, Sasha Hinkley, R. Asensio-Torres, Stefan Hippler, Roderick Dembet, Thibaut Paumard, John D. Monnier, Claudia Paladini, Valentin Christiaens, Julien Woillez, Linda J. Tacconi, Gilles Otten, Z. Hubert, V. Lapeyrère, Xavier Haubois, António Amorim, Guy Perrin, Jinyi Shangguan, Jingxiu Wang, R. Garcia Lopez, David Mouillet, Erich Wiezorrek, M. Nowak, Reinhard Genzel, Sylvestre Lacour, P. Rubini, G. Heißel, Gilles Duvert, Odele Straub, J.-B. Le Bouquin, Thomas Ott, Jens Kammerer, Anne-Lise Maire, A. Drescher, Laura Kreidberg, G. Rodríguez-Coira, O. Pfuhl, Paulo J. V. Garcia, Laurent Pueyo, A. Grandjean, Frank Eisenhauer, Yann Clénet, P. T. de Zeeuw, Pierre Léna, Matthew Horrobin, V. Coudé du Foresto, Roberto Abuter, Anne-Marie Lagrange, S. D. von Fellenberg, Tomas Stolker, Gérard Rousset, F. Vincent, Pierre Kervella, Faustine Cantalloube, Julien Girard, Andreas Eckart, Arthur Vigan, Mickael Bonnefoy, Paul Mollière, Silvia Scheithauer, André Müller, Miriam Keppler, Ekkehard Wieprecht, E. Nasedkin, Christian Straubmeier, Th. Henning, Jason Dexter, Sarah Blunt, Myriam Benisty, M. Houllé, K. Ward-Duong, Julia Stadler, A. Jiménez-Rosales, Eckhard Sturm, Laurent Jocou, M. Kulikauskas, M. Bauböck, Elodie Choquet, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: planets and satellites, Astrophysics, 01 natural sciences, Luminosity, formation -techniques, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, detection -planets and satellites, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Planetary core, Giant planet, Astronomy and Astrophysics, Orbital period, Exoplanet, Accretion (astrophysics), Radial velocity, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], interferometric, Astrophysics::Earth and Planetary Astrophysics
Abstract: Context.Methods used to detect giant exoplanets can be broadly divided into two categories: indirect and direct. Indirect methods are more sensitive to planets with a small orbital period, whereas direct detection is more sensitive to planets orbiting at a large distance from their host star. This dichotomy makes it difficult to combine the two techniques on a single target at once.Aims.Simultaneous measurements made by direct and indirect techniques offer the possibility of determining the mass and luminosity of planets and a method of testing formation models. Here, we aim to show how long-baseline interferometric observations guided by radial-velocity can be used in such a way.Methods.We observed the recently-discovered giant planetβPictoris c with GRAVITY, mounted on the Very Large Telescope Interferometer.Results.This study constitutes the first direct confirmation of a planet discovered through radial velocity. We find that the planet has a temperature ofT = 1250 ± 50 K and a dynamical mass ofM = 8.2 ± 0.8 MJup. At 18.5 ± 2.5 Myr, this putsβPic c close to a ‘hot start’ track, which is usually associated with formation via disk instability. Conversely, the planet orbits at a distance of 2.7 au, which is too close for disk instability to occur. The low apparent magnitude (MK = 14.3 ± 0.1) favours a core accretion scenario.Conclusions.We suggest that this apparent contradiction is a sign of hot core accretion, for example, due to the mass of the planetary core or the existence of a high-temperature accretion shock during formation.
Published: 2020

29. ARES. II. Characterizing the Hot Jupiters WASP-127 b, WASP-79 b, and WASP-62b with the Hubble Space Telescope

Author: William Pluriel, Jean-Philippe Beaulieu, Tiziano Zingales, Doriann Blain, Nour Skaf, Quentin Changeat, Sam Wright, Benjamin Charnay, Darius Modirrousta-Galian, Amélie Gressier, Adam Yassin Jaziri, Ahmed Al-Refaie, Robin Baeyens, Billy Edwards, Pierre Drossart, Mathilde Poveda, Ingo Waldmann, Michelle Fabienne Bieger, Jérémy Leconte, Niall Whiteford, Kai Hou Yip, Mario Morvan, Angelos Tsiaras, Flavien Kiefer, Gloria Guilluy, Olivia Venot, Lorenzo V. Mugnai, Department of Physics and Astronomy [UCL London], University College of London [London] (UCL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), College of Engineering, Mathematics and Physical Sciences [Exeter] (EMPS), University of Exeter, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ECLIPSE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Paris (UP)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Maison de la Simulation (MDLS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Instituut voor Sterrenkunde [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Dipartimento di Fisica [Torino], Università degli studi di Torino (UNITO), INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Palermo (OAPa), Department of Physics [Roma La Sapienza], Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Centre for Exoplanet Science, School of Physical Sciences [Hobart], University of Tasmania [Hobart, Australia] (UTAS), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino = University of Turin (UNITO), Dipartimento di Fisica [Roma La Sapienza], and Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA)
Subjects: Exoplanet atmospheres (487), 010504 meteorology & atmospheric sciences, Gas giant, Exoplanet astronomy, MOLECULAR OPACITIES, Exoplanet atmospheres, Astronomy data analysis, Hubble Space Telescope, MODELS, Unified Astronomy Thesaurus concepts: Exoplanet astronomy (486), Astronomy & Astrophysics, 01 natural sciences, DWARF, Astronomy data analysis (1858), CHEMISTRY, Hubble space telescope, 0103 physical sciences, Hot Jupiter, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Science & Technology, SPECTROSCOPY, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy, Astronomy and Astrophysics, Hubble Space Telescope (761), EXOPLANETS, Grism, On board, 13. Climate action, Space and Planetary Science, Physical Sciences, ROTATION, Wide Field Camera 3, ATMOSPHERIC CIRCULATION, PLANETS
Abstract: International audience; This paper presents the atmospheric characterization of three large, gaseous planets: WASP-127 b, WASP-79 b, and WASP-62 b. We analyzed spectroscopic data obtained with the G141 grism (1.088-1.68 μm) of the Wide Field Camera 3 on board the Hubble Space Telescope using the Iraclis pipeline and the TauREx3 retrieval code, both of which are publicly available. For WASP-127 b, which is the least dense planet discovered so far and is located in the short-period Neptune desert, our retrieval results found strong water absorption corresponding to an abundance of log(H2O) = -2.71 +0.78−1.05 and absorption compatible with an iron hydride abundance of log(FeH) = −5.25+0.88−1.10, with an extended cloudy atmosphere. We also detected water vapor in the atmospheres of WASP-79 b and WASP-62 b, with best-fit models indicating the presence of iron hydride, too. We used the Atmospheric Detectability Index as well as Bayesian log evidence to quantify the strength of the detection and compared our results to the hot Jupiter population study by Tsiaras et al. While all the planets studied here are suitable targets for characterization with upcoming facilities such as the James Webb Space Telescope and Ariel, WASP-127 b is of particular interest due to its low density, and a thorough atmospheric study would develop our understanding of planet formation and migration. * ARES: Ariel Retrieval of Exoplanets School.
Published: 2020

30. Orbital and spectral characterization of the benchmark T-type brown dwarf HD 19467B

Author: N. Frankel, Ronald Roelfsema, Anthony Cheetham, Jean-Loup Baudino, P. Mollière, Janis Hagelberg, Thomas Henning, Alain Roux, Michael R. Meyer, Joany Andreina Manjarres Ramos, Benjamin Charnay, Stéphane Udry, R. Galicher, C. Lazzoni, T. O. B. Schmidt, Sergio Messina, Beth Biller, Alice Zurlo, Roxanne Ligi, Mickael Bonnefoy, C. Perrot, Raffaele Gratton, Damien Ségransan, Gael Chauvin, Philippe Delorme, T. Bhowmik, A-M. Lagrange, Silvano Desidera, Dino Mesa, Anne-Lise Maire, Anthony Boccaletti, Wolfgang Brandner, E. L. Rickman, Trifon Trifonov, Maud Langlois, J. Pragt, Karan Molaverdikhani, Baptiste Lavie, Valentina D'Orazi, L. Gluck, Faustine Cantalloube, Jean-Luc Beuzit, André Müller, Arthur Vigan, J.-F. Sauvage, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
Subjects: 010504 meteorology & atmospheric sciences, planets and satellites: dynamical evolution and stability, FOS: Physical sciences, Library science, techniques: image processing, Astrophysics, 01 natural sciences, stars: individual: HD 19467, 0103 physical sciences, media_common.cataloged_instance, European union, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, media_common, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], European research, techniques: high angular resolution, Astronomy and Astrophysics, methods: data analysis, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics - Instrumentation and Methods for Astrophysics, brown dwarfs, Astrophysics - Earth and Planetary Astrophysics
Abstract: Context. Detecting and characterizing substellar companions for which the luminosity, mass, and age can be determined independently is of utter importance to test and calibrate the evolutionary models due to uncertainties in their formation mechanisms. HD 19467 is a bright and nearby star hosting a cool brown dwarf companion detected with RV and imaging, making it a valuable object for such studies. Aims. We aim to further characterize the orbital, spectral, and physical properties of the HD 19467 system. Methods. We present new high-contrast imaging data with the SPHERE and NaCo instruments. We also analyze archival data from HARPS, NaCo, HIRES, UVES, and ASAS. We also use proper motion data of the star from Hipparcos and Gaia. Results. We refine the properties of the host star and derive an age of 8.0$^{+2.0}_{-1.0}$ Gyr based on isochrones, gyrochronology, and chemical and kinematic arguments. This estimate is slightly younger than previous estimates of ~9-11 Gyr. No orbital curvature is seen in the current imaging, RV, and astrometric data. From a joint fit of the data, we refine the orbital parameters for HD 19467B: period 398$^{+95}_{-93}$ yr, inclination 129.8$^{+8.1}_{-5.1}$ deg, eccentricity 0.56$\pm$0.09, longitude of the ascending node 134.8$\pm$4.5 deg, and argument of the periastron 64.2$^{+5.5}_{-6.3}$ deg. We assess a dynamical mass of 74$^{+12}_{-9}$ MJ. The fit with atmospheric models of the spectrophotometric data of HD 19467B indicates an atmosphere without clouds or with very thin clouds, an effective temperature of 1042$^{+77}_{-71}$ K, and a large surface gravity of 5.34$^{+0.08}_{-0.09}$ dex. The comparison to model predictions of the bolometric luminosity and dynamical mass of HD 19467B, assuming our system age estimate, indicates a better agreement with the Burrows et al. models; whereas the other evolutionary models used tend to underestimate its cooling rate., Accepted for publication in A&A, 25 pages, 23 figures, 9 tables. Abstract slightly abridged to match arXiv requirements. Updated after language editing
Published: 2020

31. ARES I: WASP-76 b, A Tale of Two HST Spectra

Author: Sam Wright, Angelos Tsiaras, Mario Morvan, Mathilde Poveda, Ahmed Al-Refaie, Pierre Drossart, Gloria Guilluy, Amélie Gressier, Olivia Venot, William Pluriel, Lorenzo V. Mugnai, Flavien Kiefer, Tiziano Zingales, Niall Whiteford, Robin Baeyens, Ingo Waldmann, Billy Edwards, Adam Yassin Jaziri, Jean-Philippe Beaulieu, Darius Modirrousta-Galian, Doriann Blain, Jake Taylor, Quentin Changeat, Nour Skaf, Benjamin Charnay, Michelle Fabienne Bieger, Jérémy Leconte, Kai Hou Yip, Department of Physics and Astronomy [UCL London], University College of London [London] (UCL), Instituut voor Sterrenkunde [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford [Oxford], College of Engineering, Mathematics and Physical Sciences [Exeter] (EMPS), University of Exeter, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Dipartimento di Fisica [Torino], Università degli studi di Torino (UNITO), INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), ECLIPSE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Palermo (OAPa), Dipartimento di Fisica e Chimica [Palermo] (DiFC), Università degli studi di Palermo - University of Palermo, Department of Physics [Roma La Sapienza], Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Centre for Exoplanet Science, School of Physical Sciences [Hobart], University of Tasmania [Hobart, Australia] (UTAS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino = University of Turin (UNITO), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of Oxford, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), and Dipartimento di Fisica [Roma La Sapienza]
Subjects: Brightness, 010504 meteorology & atmospheric sciences, Exoplanet atmospheres, Exoplanet atmospheric composition, Hubble Space Telescope, Astrophysics - Earth and Planetary Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astronomy & Astrophysics, 01 natural sciences, Spectral line, Atmosphere, Jupiter, HAT-P-7B, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Emission spectrum, MOLECULAR LINE LISTS, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, HOT, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Science & Technology, Astronomy and Astrophysics, ATMOSPHERE, GIANT EXOPLANET, Grism, RESOLUTION, Transmission (telecommunications), 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Physical Sciences, INFERENCE, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Wide Field Camera 3, STARS
Abstract: 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 reduce and fit the raw data for each observation using the open-source software Iraclis before performing a fully Bayesian retrieval using the publicly available analysis suite TauRex 3. Previous studies of the WFC3 transmission spectra of WASP-76 b found hints of titanium oxide (TiO) and vanadium oxide (VO) or non-grey clouds. Accounting for a fainter stellar companion to WASP-76, we reanalyse this data and show that removing the effects of this background star changes the slope of the spectrum, resulting in these visible absorbers no longer being detected, eliminating the need for a non-grey cloud model to adequately fit the data but maintaining the strong water feature previously seen. However, our analysis of the emission spectrum suggests the presence of TiO and an atmospheric thermal inversion, along with a significant amount of water. Given the brightness of the host star and the size of the atmospheric features, WASP-76 b is an excellent target for further characterisation with HST, or with future facilities, to better understand the nature of its atmosphere, to confirm the presence of TiO and to search for other optical absorbers., Accepted for publication in AJ
Published: 2020

32. Is the Faint Young Sun Problem for Earth Solved?

Author: Benjamin Charnay, Bernard Marty, Eric T. Wolf, François Forget, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), University of Colorado [Boulder], Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Observatoire de Paris, and Université Paris sciences et lettres (PSL)
Subjects: 010504 meteorology & atmospheric sciences, Habitability, Solar luminosity, FOS: Physical sciences, 01 natural sciences, Astrobiology, Physics::Geophysics, Atmosphere, 0103 physical sciences, Paleoclimatology, Astrophysics::Solar and Stellar Astrophysics, Paleoclimates, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Astronomy and Astrophysics, Early Earth, Mars Exploration Program, Exoplanet, Planetary science, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Physics::Space Physics, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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 evidence for the presence of liquid water on Earth's surface at that time. This "faint young Sun problem" is a fundamental question in paleoclimatology, with important implications for the habitability of the early Earth, early Mars and exoplanets. Many solutions have been proposed based on the effects of greenhouse gases, atmospheric pressure, clouds, land distribution and Earth's rotation rate. Here we review the faint young Sun problem for Earth, highlighting the latest geological and geochemical constraints on the early Earth's atmosphere, and recent results from 3D global climate models and carbon cycle models. Based on these works, we argue that the faint young Sun problem for Earth has essentially been solved. Unfrozen Archean oceans were likely maintained by higher concentrations of CO2, consistent with the latest geological proxies, potentially helped by additional warming processes. This reinforces the expected key role of the carbon cycle for maintaining the habitability of terrestrial planets. Additional constraints on the Archean atmosphere and 3D fully coupled atmosphere-ocean models are required to validate this conclusion., 22 pages, 7 figures, 1 table. Accepted for publication in Space Science Reviews. Part of ISSI special collection on Diversity of Atmospheres
Published: 2020

33. Peering into the formation history of β Pictoris b with VLTI/GRAVITY long-baseline interferometry

Author: Gérard Rousset, N. M. Förster Schreiber, E. F. van Dishoeck, Laurent Pueyo, Frank Eisenhauer, Pierre Léna, H. Bonnet, Jingxiu Wang, Eric Gendron, Stefan Gillessen, Anne-Lise Maire, Yann Clénet, P. T. de Zeeuw, Hervé Beust, Jinyi Shangguan, S. Yazici, Julien Woillez, Thibaut Paumard, Claudia Paladini, C. Collin, M. Nowak, Sylvestre Lacour, Thomas Ott, D. Ziegler, F. Chapron, António Amorim, Erich Wiezorrek, Oliver Pfuhl, Feng Gao, A. Buron, P. Fédou, Z. Hubert, R. Garcia Lopez, Reinhard Genzel, Wolfgang Brandner, Odele Straub, J.-B. Le Bouquin, Ekkehard Wieprecht, Jean-Phillipe Berger, Stefan Hippler, Benjamin Charnay, Eckhard Sturm, F. Vincent, Pierre Kervella, Faustine Cantalloube, Laurent Jocou, G. Rodríguez-Coira, Sebastian Rabien, Roberto Abuter, Anne-Marie Lagrange, Mickael Bonnefoy, C. Rau, Linda J. Tacconi, Guy Perrin, Andreas Eckart, Silvia Scheithauer, Felix Widmann, Karine Perraut, V. Lapeyrère, P. Mollière, Gilles Duvert, Christian Straubmeier, F. Haußmann, Th. Henning, Jason Dexter, V. Coudé du Foresto, R. Dembet, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: Planetesimal, 010504 meteorology & atmospheric sciences, planets and satellites, formation -planets and satellites, atmospheres -techniques, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, β Pictoris, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, individual, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Orbital elements, Physics, [PHYS]Physics [physics], Earth and Planetary Astrophysics (astro-ph.EP), Very Large Telescope, Giant planet, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Astrometry, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics::Earth and Planetary Astrophysics, interferometricstars, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Instrumentation and Methods for Astrophysics, Planetary mass, Astrophysics - Earth and Planetary Astrophysics
Abstract: Our objective is to estimate the C/O ratio in the atmosphere of beta Pictoris b and obtain an estimate of the dynamical mass of the planet, as well as to refine its orbital parameters using high-precision astrometry. We used the GRAVITY instrument with the four 8.2 m telescopes of the Very Large Telescope Interferometer to obtain K-band spectro-interferometric data on $\beta$ Pic b. We extracted a medium resolution (R=500) K-band spectrum of the planet and a high-precision astrometric position. We estimated the planetary C/O ratio using two different approaches (forward modeling and free retrieval) from two different codes (ExoREM and petitRADTRANS, respectively). Finally, we used a simplified model of two formation scenarios (gravitational collapse and core-accretion) to determine which can best explain the measured C/O ratio. Our new astrometry disfavors a circular orbit for $\beta$ Pic b ($e=0.15^{+0.05}_{-0.04}$). Combined with previous results and with Hipparcos/GAIA measurements, this astrometry points to a planet mass of $M = 12.7\pm{}2.2\,M_\mathrm{Jup}$. This value is compatible with the mass derived with the free-retrieval code petitRADTRANS using spectral data only. The forward modeling and free-retrieval approches yield very similar results regarding the atmosphere of beta Pic b. In particular, the C/O ratios derived with the two codes are identical ($0.43\pm{}0.05$ vs $0.43^{+0.04}_{-0.03}$). We argue that if the stellar C/O in $\beta$ Pic is Solar, then this combination of a very high mass and a low C/O ratio for the planet suggests a formation through core-accretion, with strong planetesimal enrichment., Comment: 14 pages + 7 page appendix, 7 figures, accepted for pulication
Published: 2020

34. Possible Atmospheric Diversity of Low Mass Exoplanets – Some Central Aspects

Author: Emeline Bolmont, Benjamin Charnay, Mareike Godolt, François Forget, John Lee Grenfell, Martin Turbet, Óscar Carrión-González, Jérémy Leconte, Lena Noack, Heike Rauer, Feng Tian, Fabrice Gaillard, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Zentrum für Astronomie und Astrophysik [Berlin] (ZAA), Technische Universität Berlin (TU), Institut für Geologische Wissenschaften, Freie Universität Berlin, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Observatoire de Paris, Université Paris sciences et lettres (PSL), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC)
Subjects: Solar System, 010504 meteorology & atmospheric sciences, media_common.quotation_subject, review, Exoplanetology, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Context (language use), 01 natural sciences, diversity, Astrobiology, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, media_common, Earth and Planetary Astrophysics (astro-ph.EP), Atmospheric models, exoplanetary, Astronomy and Astrophysics, Exoplanet, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, atmospheres, Environmental science, Astrophysics::Earth and Planetary Astrophysics, Low Mass, Astrophysics - Earth and Planetary Astrophysics, Diversity (politics), Exosphere
Abstract: International audience; 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 atmospheres which could exist in nature. We are motivated by newly emerging observations, refined approaches to address data degeneracies, improved theories for key processes affecting atmospheric evolution and a new generation of atmospheric models which couple physical processes from the deep interior through to the exosphere and consider the planetary-star system as a whole. Using the Solar System as our guide we first summarize the main processes which sculpt atmospheric evolution then discuss their potential interactions in the context of exoplanetary environments. We summarize key uncertainties and consider a diverse range of atmospheric compositions discussing their potential occurrence in an exoplanetary context.
Published: 2020
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35. Nitrogen Oxides in Early Earth's Atmosphere as Electron Acceptors for Life's Emergence

Author: Michael J. Russell, Michael L. Wong, Peter Gao, Yuk L. Yung, Benjamin Charnay, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), and NASA-California Institute of Technology (CALTECH)
Subjects: 010504 meteorology & atmospheric sciences, Earth, Planet, Hadean, Origin of Life, Inorganic chemistry, Electrons, 7. Clean energy, 01 natural sciences, Redox, Atmosphere, chemistry.chemical_compound, Hydrothermal Vents, Nitrate, Abiogenesis, 0103 physical sciences, Nitrite, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, NOx, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Photochemical Processes, Early Earth, Agricultural and Biological Sciences (miscellaneous), Models, Chemical, chemistry, 13. Climate action, Space and Planetary Science, Environmental chemistry, Nitrogen Oxides, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Oxidation-Reduction
Abstract: We quantify the amount of nitrogen oxides (NOx) produced through lightning and photochemical processes in the Hadean atmosphere to be available in the Hadean ocean for the emergence of life. Atmospherically generated nitrate (NO_3−) and nitrite (NO_2−) are the most attractive high-potential electron acceptors for pulling and enabling crucial redox reactions of autotrophic metabolic pathways at submarine alkaline hydrothermal vents. The Hadean atmosphere, dominated by CO_2 and N_2, will produce nitric oxide (NO) when shocked by lightning. Photochemical reactions involving NO and H_2O vapor will then produce acids such as HNO, HNO_2, HNO_3, and HO_2NO_2 that rain into the ocean. There, they dissociate into or react to form nitrate and nitrite. We present new calculations based on a novel combination of early-Earth global climate model and photochemical modeling, and we predict the flux of NOx to the Hadean ocean. In our 0.1-, 1-, and 10-bar pCO_2 models, we calculate the NOx delivery to be 2.4 × 10^5, 6.5 × 10^8, and 1.9 × 10^8 molecules cm^(−2) s^(−1). After only tens of thousands to tens of millions of years, these NOx fluxes are expected to produce sufficient (micromolar) ocean concentrations of high-potential electron acceptors for the emergence of life.
Published: 2017

36. Spectral and orbital characterisation of the directly imaged giant planet HIP 65426 b

Author: P. Delorme, R. van Boekel, N. Godoy, Anne-Marie Lagrange, D. Segransan, Markus Janson, Ralf Launhardt, M. Samland, Faustine Cantalloube, Benjamin Charnay, Michael Meyer, Johan Olofsson, Miriam Keppler, Henning Avenhaus, Stéphane Udry, Andreas Quirrenbach, Sascha P. Quanz, T. O. B. Schmidt, E. Sissa, M. Bonnefoy, D. Queloz, Sabine Reffert, A. Musso Barcucci, G. Chauvin, Dino Mesa, G. Cugno, S. S. Brems, A. Boccaletti, Grant M. Kennedy, Francesco Pepe, A. Mueller, Maud Langlois, C. Lazzoni, Anthony Cheetham, Th. Henning, Julien Girard, Francois Menard, Stanimir Metchev, Anne-Lise Maire, A. Zurlo, E. L. Rickman, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Brown dwarf, FOS: Physical sciences, Astrophysics, 01 natural sciences, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Inclined orbit, 010308 nuclear & particles physics, Astronomy and Astrophysics, Effective temperature, Surface gravity, Orbital period, Exoplanet, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Orbital motion, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: HIP 65426 b is a recently discovered exoplanet imaged during the course of the SPHERE-SHINE survey. Here we present new $L'$ and $M'$ observations of the planet from the NACO instrument at the VLT from the NACO-ISPY survey, as well as a new $Y-H$ spectrum and $K$-band photometry from SPHERE-SHINE. Using these data, we confirm the nature of the companion as a warm, dusty planet with a mid-L spectral type. From comparison of its SED with the BT-Settl atmospheric models, we derive a best-fit effective temperature of $T_{\text{eff}}=1618\pm7$ K, surface gravity $\log g=3.78^{+0.04}_{-0.03}$ and radius $R=1.17\pm0.04$ $R_{\text{J}}$ (statistical uncertainties only). Using the DUSTY and COND isochrones we estimate a mass of $8\pm1$ $M_{\text{J}}$. Combining the astrometric measurements from our new datasets and from the literature, we show the first indications of orbital motion of the companion (2.6$\sigma$ significance) and derive preliminary orbital constraints. We find a highly inclined orbit ($i=107^{+13}_{-10}$ deg) with an orbital period of $800^{+1200}_{-400}$ yr. We also report SPHERE sparse aperture masking observations that investigate the possibility that HIP 65426 b was scattered onto its current orbit by an additional companion at a smaller orbital separation. From this data we rule out the presence of brown dwarf companions with masses greater than 16 $M_{\text{J}}$ at separations larger than 3 AU, significantly narrowing the parameter space for such a companion., Comment: Accepted for publication in A&A
Published: 2019

37. Effects of a fully 3D atmospheric structure on exoplanet transmission spectra: retrieval biases due to day–night temperature gradients

Author: Franck Selsis, Marco Rocchetto, Benjamin Charnay, Anthony Caldas, Jérémy Leconte, Pascal Borde, Ingo Waldmann, ECLIPSE 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Verona (UNIVR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, 01 natural sciences, Spectral line, Atmosphere, Planet, 0103 physical sciences, Thermal, Annulus (firestop), Radiative transfer, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Earth and Planetary Astrophysics (astro-ph.EP), Physics, planets and satellites: atmospheres, [PHYS]Physics [physics], Ground truth, Astronomy and Astrophysics, planets and satellites: general, Exoplanet, 13. Climate action, Space and Planetary Science, radiative transfer, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], techniques: spectroscopic, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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. Consequently, studies have focused on the effect of atmospheric horizontal heterogeneities along the limb. Here we demonstrate that the region probed in transmission -- the limb -- extends significantly toward the day and night sides of the planet. We show that the strong day-night thermal and compositional gradients expected on synchronous exoplanets create sufficient heterogeneities across the limb to result in important systematic effects on the spectrum and bias its interpretation. To quantify these effects, we developed a 3D radiative transfer model able to generate transmission spectra of atmospheres based on 3D atmospheric structures. We first produce synthetic JWST observations from a simulation of GJ 1214b and demonstrate the necessity of a real 3D approach to model data for such precise observatories. Second, we investigate how day-night temperature gradients cause a systematic bias in retrieval analysis performed with 1D forward models. For that purpose we synthesize a large set of forward spectra for prototypical HD 209458 b and GJ 1214 b type planets varying the temperatures of the day and night sides as well as the width of the transition region. We then perform typical retrieval analyses and compare the retrieved parameters to the ground truth of the input model. This study reveals systematic biases on the retrieved temperature (found to be higher than the terminator temperature) and abundances. This is due to the fact that the hotter dayside is more extended vertically and screens the nightside. These biases are difficult to detect as the 1D profiles used in the retrieval are found to provide an excellent match to the observed spectra. This needs to be kept in mind when interpreting real data., Comment: Accepted for publication at Astronomy and Astrophysics. Abstract abridged to meet ArXiv size limit
Published: 2019

38. VLT/SPHERE exploration of the young multiplanetary system PDS70

Author: Eric Lagadec, Benjamin Charnay, E. Cascone, L. Rodet, R. Ligi, Markus Janson, T. O. B. Schmidt, Anthony Boccaletti, André Müller, Christophe Pinte, Th. Henning, S. Antoniucci, Anne-Lise Maire, Jaehan Bae, Matthias Samland, Arthur Vigan, Anthony Cheetham, L. Weber, N. Meunier, Patrice Martinez, Daniel Rouan, Maud Langlois, S. Petrus, Myriam Benisty, S. Brown Sevilla, M. Keppler, Raffaele Gratton, C. Lazzoni, Markus Feldt, S. Rochat, J. de Boer, Julien Milli, Jean-François Sauvage, Faustine Cantalloube, O. Flasseur, Valentina D'Orazi, Silvano Desidera, Francois Wildi, François Ménard, Riccardo Claudi, Philippe Delorme, Gael Chauvin, A-M. Lagrange, C. Perrot, Dino Mesa, Alice Zurlo, E. L. Rickman, Benoît Pairet, Michael R. Meyer, Stéphane Udry, Mickael Bonnefoy, Jean-Loup Baudino, Janis Hagelberg, Quentin Kral, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Carnegie Institution for Science, Leiden Observatory [Leiden], Universiteit Leiden, University of Michigan [Ann Arbor], University of Michigan System, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hubert Curien [Saint Etienne] (LHC), Université Jean Monnet [Saint-Étienne] (UJM)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS), Carnegie Institution for Science [Washington], Universiteit Leiden [Leiden], European Southern Observatory (ESO), Institute of Information and Communication Technologies, Electronics and Applied Mathematics (ICTEAM), Université Catholique de Louvain = Catholic University of Louvain (UCL), INAF - Osservatorio Astronomico di Roma (OAR), INAF - Osservatorio Astronomico di Capodimonte (OAC), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Geneva Observatory, University of Geneva [Switzerland], Stockholm Observatory Department of Astronomy, Stockholm University, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA), DOTA, ONERA, Université Paris Saclay (COmUE) [Palaiseau], ONERA-Université Paris Saclay (COmUE), National Oceanography Centre [Southampton] (NOC), University of Southampton, Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hubert Curien (LHC), Institut d'Optique Graduate School (IOGS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Université de Genève = University of Geneva (UNIGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Data analysis, FOS: Physical sciences, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Star (graph theory), 01 natural sciences, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], Spectrograph, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Astronomy and Astrophysics, Spectral bands, Planetary system, Imaging spectroscopy, Andromeda, Planetary systems, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, PDS 70, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Planetary mass, Astrophysics - Earth and Planetary Astrophysics, Data reduction
Abstract: Context. PDS 70 is a young (5.4 Myr), nearby (~113 pc) star hosting a known transition disk with a large gap. Recent observations with SPHERE and NACO in the near-infrared (NIR) allowed us to detect a planetary mass companion, PDS70b, within the disk cavity. Moreover, observations in H_alpha with MagAO and MUSE revealed emission associated to PDS70b and to another new companion candidate, PDS70c, at a larger separation from the star. Aims. Our aim is to confirm the discovery of the second planet PDS70c using SPHERE at VLT, to further characterize its physical properties, and search for additional point sources in this young planetary system. Methods. We re-analyzed archival SPHERE NIR observations and obtained new data in Y, J, H and K spectral bands for a total of four different epochs. The data were reduced using the data reduction and handling pipeline and the SPHERE data center. We then applied custom routines (e.g. ANDROMEDA and PACO) to subtract the starlight. Results. We re-detect both PDS 70 b and c and confirm that PDS70c is gravitationally bound to the star. We estimate this second planet to be less massive than 5 M Jup and with a T_eff around 900 K. Also, it has a low gravity with log g between 3.0 and 3.5 dex. In addition, a third object has been identified at short separation (~0.12") from the star and gravitationally bound to the star. Its spectrum is however very blue, so that we are probably seeing stellar light reflected by dust and our analysis seems to demonstrate that it is a feature of the inner disk. We, however, cannot completely exclude the possibility that it is a planetary mass object enshrouded by a dust envelope. In this latter case, its mass should be of the order of few tens of M_Earth. Moreover, we propose a possible structure for the planetary system based on our data that, however, cannot be stable on a long timescale., Accepted by A&A - 12 pages - 9 figures
Published: 2019
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39. Reduced chemical scheme for modelling warm to hot hydrogen-dominated atmospheres

Author: Benjamin Charnay, Roda Bounaceur, Michel Dobrijevic, Pascal Tremblin, Thibault Cavalié, Olivia Venot, Eric Hébrard, Benjamin Drummond, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Réactions et Génie des Procédés (LRGP), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), ASP 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, School of Physics and Astronomy [Exeter], University of Exeter, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
Subjects: Solar System, 010504 meteorology & atmospheric sciences, Brown dwarf, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, 01 natural sciences, methods: numerical, Atmosphere, Jupiter, Planet, Neptune, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), planets and satellites: atmospheres, [PHYS]Physics [physics], Physics, astrochemistry, planets and satellites: composition, Uranus, Astronomy and Astrophysics, Exoplanet, planets and satellites: gaseous planets, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], brown dwarfs, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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 future telescopes. Recent Juno observations of the NH3 tropospheric distribution in Jupiter also indicate that 3D chemical modelling may be necessary to constrain the deep composition of the giant planets of the Solar System. However, due to the high computational cost of chemistry calculations, 3D chemical modelling has so far been limited. A solution to include chemical kinetics in a 3D model is to use a reduced chemical scheme. In this view, we have developed a reduced scheme containing 30 species and 181 reversible reactions, from the full chemical scheme of Venot et al. 2012. This scheme reproduces accurately the vertical profiles of the observable species (H2O, CH4, CO, CO2, NH3, and HCN) and has a large range of validity. It can be used to study all kind of warm atmospheres, except hot C-rich ones, which contains a high amount of C2H2. It can be used in 1D models, for fast computations, but also in 3D models for hot giant (exo)planet and brown dwarf atmospheres., 13 pages, 11 figures, accepted for publication in A&A
Published: 2019

40. 1D atmospheric study of the temperate sub-Neptune K2-18b

Author: Doriann Blain, Bruno Bézard, Benjamin Charnay, Observatoire de Paris, and Université Paris sciences et lettres (PSL)
Subjects: molecular data, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, Overfitting, Space (mathematics), 01 natural sciences, Atmosphere, Neptune, 0103 physical sciences, Range (statistics), infrared: planetary systems, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), planets and satellites: atmospheres, Physics, Astronomy and Astrophysics, Exoplanet, planets and satellites: gaseous planets, Transmission (telecommunications), 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The atmospheric composition of exoplanets with masses between 2 and 10 M$_\oplus$ is poorly understood. In that regard, the sub-Neptune K2-18b, which is subject to Earth-like stellar irradiation, offers a valuable opportunity for the characterisation of such atmospheres. Previous analyses of its transmission spectrum from the Kepler, Hubble (HST), and Spitzer space telescopes data using both retrieval algorithms and forward-modelling suggest the presence of H$_2$O and an H$_2$--He atmosphere, but have not detected other gases, such as CH$_4$. We present simulations of the atmosphere of K2-18 b using Exo-REM, our self-consistent 1D radiative-equilibrium model, using a large grid of atmospheric parameters to infer constraints on its chemical composition. We show that our simulations favour atmospheric metallicities between 40 and 500 times solar and indicate, in some cases, the formation of H$_2$O-ice clouds, but not liquid H$_2$O clouds. We also confirm the findings of our previous study, which showed that CH$_4$ absorption features nominally dominate the transmission spectrum in the HST spectral range. We compare our results with results from retrieval algorithms and find that the H$_2$O-dominated spectrum interpretation is either due to the omission of CH$_4$ absorptions or a strong overfitting of the data. Finally, we investigated different scenarios that would allow for a CH$_4$-depleted atmosphere. We were able to fit the data to those scenarios, finding, however, that it is very unlikely for K2-18b to have a high internal temperature. A low C/O ratio ($\approx$ 0.01--0.1) allows for H$_2$O to dominate the transmission spectrum and can fit the data but so far, this set-up lacks a physical explanation. Simulations with a C/O ratio $, Comment: Accepted for publication in Astronomy & Astrophysics ; Exo-REM code and k-coefficients tables available here: https://gitlab.obspm.fr/dblain/exorem
Published: 2021

41. The Effect of Orbital Configuration on the Possible Climates and Habitability of Kepler-62f

Author: Rory Barnes, Aomawa L. Shields, Benjamin Charnay, Cecilia M. Bitz, Victoria S. Meadows, and Eric Agol
Subjects: Extraterrestrial Environment, Rotation, 010504 meteorology & atmospheric sciences, Climate, media_common.quotation_subject, Habitability, FOS: Physical sciences, Planets, Orbital eccentricity, Astronomy & Astrophysics, 01 natural sciences, 7. Clean energy, Astrobiology, Atmosphere, Planetary environments, Planet, Exobiology, 0103 physical sciences, Solstice, Computer Simulation, Eccentricity (behavior), 010303 astronomy & astrophysics, Research Articles, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, media_common, Earth and Planetary Astrophysics (astro-ph.EP), Planetary habitability, Ice, Temperature, Geology, Carbon Dioxide, Agricultural and Biological Sciences (miscellaneous), Tidal locking, Extrasolar planets, Geochemistry, 13. Climate action, Space and Planetary Science, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, Astronomical and Space Sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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 we explore a specific case, Kepler-62f, a potentially habitable planet in a five-planet system with a K2V host star. N-body integrations reveal the stable range of initial eccentricities for Kepler-62f is $0.00 \leqslant e \leqslant 0.32$, absent the effect of additional, undetected planets. We simulate the tidal evolution of Kepler-62f in this range and find that, for certain assumptions, the planet can be locked in a synchronous rotation state. Simulations using LMD Generic GCM indicate that with 3 bars of CO$_2$ in its atmosphere, Kepler-62f would only be warm enough for surface liquid water at the upper limit of this eccentricity range, providing it has a high planetary obliquity (between 60$^\circ$ and 90$^\circ$). A climate similar to modern-day Earth is possible for the entire range of stable eccentricities if atmospheric CO$_2$ is increased to 5-bar levels. In a low-CO$_2$ case, simulations with CCSM4 and LMD Generic GCM indicate that increases in planetary obliquity and orbital eccentricity coupled with an orbital configuration that places the summer solstice at or near pericenter permit regions of the planet with above-freezing surface temperatures. This may melt ice sheets formed during colder seasons. If Kepler-62f is synchronously rotating and has an ocean, CO$_2$ levels above 3 bars would be required to distribute enough heat to the night side of the planet to avoid atmospheric freeze-out and permit a large enough region of open water at the planet's substellar point to remain stable. Overall, we find multiple plausible combinations of orbital and atmospheric properties that permit surface liquid water on Kepler-62f., 68 pages, 14 figures, 6 tables, accepted for publication in Astrobiology
Published: 2016

42. Publisher Correction: Formation of secondary atmospheres on terrestrial planets by late disk accretion

Author: Jeanne Davoult, Quentin Kral, and Benjamin Charnay
Subjects: Terrestrial planet, Astronomy and Astrophysics, Accretion (astrophysics), Geology, Astrobiology
Published: 2020

43. Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e

Author: Frank Eisenhauer, Th. Henning, P. Mollière, Jingxiu Wang, E. F. van Dishoeck, T. Molyarova, Jinyi Shangguan, Pierre Kervella, Tomas Stolker, Alexandra Z. Greenbaum, Mathias Nowak, Sylvestre Lacour, Alice Zurlo, E. Nasedkin, Gabriel-Dominique Marleau, Gilles Otten, D. Semenov, Anne-Lise Maire, Ignas Snellen, Laurent Pueyo, Sasha Hinkley, Arthur Vigan, Laura Kreidberg, Benjamin Charnay, Paulo J. V. Garcia, Julien Girard, P. T. de Zeeuw, R. Garcia Lopez, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, European Southern Observatory (ESO), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)
Subjects: 010504 meteorology & atmospheric sciences, Opacity, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, Spectral line, methods: numerical, Atmosphere, Planet, 0103 physical sciences, Radiative transfer, 010303 astronomy & astrophysics, instrumentation: spectrographs, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), planets and satellites: atmospheres, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Scattering, Astronomy and Astrophysics, Exoplanet, radiative transfer, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: Clouds are ubiquitous in exoplanet atmospheres and represent a challenge for the model interpretation of their spectra. Complex cloud models are too numerically costly for generating a large number of spectra, while more efficient models may be too strongly simplified. We aim to constrain the atmospheric properties of the directly imaged planet HR 8799e with a free retrieval approach. We use our radiative transfer code petitRADTRANS for generating spectra, which we couple to the PyMultiNest tool. We added the effect of multiple scattering which is important for treating clouds. Two cloud model parameterizations are tested: the first incorporates the mixing and settling of condensates, the second simply parameterizes the functional form of the opacity. In mock retrievals, using an inadequate cloud model may result in atmospheres that are more isothermal and less cloudy than the input. Applying our framework on observations of HR 8799e made with the GPI, SPHERE and GRAVITY, we find a cloudy atmosphere governed by disequilibrium chemistry, confirming previous analyses. We retrieve that ${\rm C/O}=0.60_{-0.08}^{+0.07}$. Other models have not yet produced a well constrained C/O value for this planet. The retrieved C/O values of both cloud models are consistent, while leading to different atmospheric structures: cloudy, or more isothermal and less cloudy. Fitting the observations with the self-consistent Exo-REM model leads to comparable results, while not constraining C/O. With data from the most sensitive instruments, retrieval analyses of directly imaged planets are possible. The inferred C/O ratio of HR 8799e is independent of the cloud model and thus appears to be a robust. This C/O is consistent with stellar, which could indicate that the HR 8799e formed outside the CO$_2$ or CO iceline. As it is the innermost planet of the system, this constraint could apply to all HR 8799 planets., Comment: Accepted for publication in A&A, 28 pages, 13 figures, updated author list
Published: 2020

44. Observational evidence for active dust storms on Titan at equinox

Author: Clément Narteau, Roger N. Clark, Benjamin Charnay, T. Appéré, S. Courrech du Pont, Jason M. Soderblom, Thomas Cornet, B. J. Buratti, J. Bow, G. Vixie, Jasper F. Kok, Jason W. Barnes, Ralf Jaumann, Philip D. Nicholson, Mathieu Hirtzig, Pascal Rannou, S. Le Mouélic, Olivier Bourgeois, Jani Radebaugh, L. Maltagliati, Ralph D. Lorenz, Kevin H. Baines, Sebastien Rodriguez, Robert H. Brown, Christophe Sotin, Antoine Lucas, S. Rafkin, Caitlin A. Griffith, Katrin Stephan, Athena Coustenis, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), College of Earth, Ocean and Atmospheric Sciences [Corvallis] (CEOAS), Oregon State University (OSU), Christ University, Bangalore, India, Department of Space Studies [Boulder], Southwest Research Institute [Boulder] (SwRI), University of Arizona, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Geological Sciences [BYU], Brigham Young University (BYU), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), Department of Planetary Sciences [Tucson], University of Idaho [Moscow, USA], Matière et Systèmes Complexes (MSC (UMR_7057)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), DLR Institute of Planetary Research, German Aerospace Center (DLR), Faculty of Sciences [Lebanese University], Lebanese University [Beirut] (LU), John Innes Centre [Norwich], Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH)-NASA, Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Southwest Research Institute [San Antonio] (SwRI), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Centre de physique moléculaire optique et hertzienne (CPMOH), Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1, Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Lebanese University [Beirut], Laboratoire d'Electronique et des Technologies de l'Information (CEA-LETI), Université Grenoble Alpes (UGA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Centre National de la Recherche Scientifique (CNRS), and Matière et Systèmes Complexes (MSC)
Subjects: Haze, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Equator, Equinox, 01 natural sciences, Methane, Astrobiology, chemistry.chemical_compound, symbols.namesake, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, dust storm, 0103 physical sciences, Radiative transfer, Meteorology & Atmospheric Sciences, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [MATH]Mathematics [math], [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Storm, Planetengeologie, chemistry, 13. Climate action, [SDU]Sciences of the Universe [physics], symbols, General Earth and Planetary Sciences, Aeolian processes, Cassini, Titan, Titan (rocket family)
Abstract: Saturn’s moon Titan has a dense nitrogen-rich atmosphere, with methane as its primary volatile. Titan’s atmosphere experiences an active chemistry that produces a haze of organic aerosols that settle to the surface and a dynamic climate in which hydrocarbons are cycled between clouds, rain and seas. Titan displays particularly energetic meteorology at equinox in equatorial regions, including sporadic and large methane storms. In 2009 and 2010, near Titan’s northern spring equinox, the Cassini spacecraft observed three distinctive and short-lived spectral brightenings close to the equator. Here, we show from analyses of Cassini spectral data, radiative transfer modelling and atmospheric simulations that the brightenings originate in the atmosphere and are consistent with formation from dust storms composed of micrometre-sized solid organic particles mobilized from underlying dune fields. Although the Huygens lander found evidence that dust can be kicked up locally from Titan’s surface, our findings suggest that dust can be suspended in Titan’s atmosphere at much larger spatial scale. Mobilization of dust and injection into the atmosphere would require dry conditions and unusually strong near-surface winds (about five times more than estimated ambient winds). Such strong winds are expected to occur in downbursts during rare equinoctial methane storms—consistent with the timing of the observed brightenings. Our findings imply that Titan—like Earth and Mars—has an active dust cycle, which suggests that Titan’s dune fields are actively evolving by aeolian processes. Saturn’s moon Titan may have an active dust cycle in equatorial regions driven by storm winds, Cassini observations consistent with dust suspension in Titan’s atmosphere suggest.
Published: 2018

45. Exo-Milankovitch Cycles. II. Climates of G-dwarf Planets in Dynamically Hot Systems

Author: Rory Barnes, David P. Fleming, Thomas R. Quinn, Caitlyn Wilhelm, Russell Deitrick, Cecilia M. Bitz, Victoria S. Meadows, John C. Armstrong, Benjamin Charnay, University of Glasgow, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Spitzer Science Center, Department of Astronomy, University of Washington [Seattle], Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Orbital forcing, 530 Physics, FOS: Physical sciences, 01 natural sciences, Astrobiology, Physics::Geophysics, Planet, 0103 physical sciences, Ice age, 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], geography, geography.geographical_feature_category, Milankovitch cycles, Planetary habitability, 520 Astronomy, Astronomy and Astrophysics, Planetary system, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Ice sheet, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Circumstellar habitable zone, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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 variations. We find that ice caps couple strongly to the orbital forcing, leading to extreme ice ages. In contrast with previous studies, we find that such exo-Milankovitch cycles tend to impair habitability by inducing snowball states within the habitable zone. The large amplitude changes in obliquity and eccentricity cause the ice edge, the lowest latitude extent of the ice caps, to become unstable and grow to the equator. We apply an analytical theory of the ice edge latitude to show that obliquity is the primary driver of the instability. The thermal inertia of the ice sheets and the spectral energy distribution of the G dwarf star increase the sensitivity of the model to triggering runaway glaciation. Finally, we apply a machine learning algorithm to demonstrate how this technique can be used to extend the power of climate models. This work illustrates the importance of orbital evolution for habitability in dynamically rich planetary systems. We emphasize that as potentially habitable planets are discovered around G dwarfs, we need to consider orbital dynamics., Comment: 37 pages, 26 figures, accepted at the Astronomical Journal
Published: 2018

46. Simultaneous Multiwavelength Variability Characterization of the Free-floating Planetary-mass Object PSO J318.5-22

Author: Beth A. Biller, Johanna Vos, Esther Buenzli, Katelyn Allers, Mickaël Bonnefoy, Benjamin Charnay, Bruno Bézard, France Allard, Derek Homeier, Mariangela Bonavita, Wolfgang Brandner, Ian Crossfield, Trent Dupuy, Thomas Henning, Taisiya Kopytova, Michael C. Liu, Elena Manjavacas, Joshua Schlieder, University of Edinburgh, Institute for Particle Physics and Astrophysics [ETH Zürich] (IPA), Department of Physics [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology (MIT), Institute for Astronomy (IfA), University of Hawai‘i [Mānoa] (UHM), Department of Computer Science [ETH Zürich] (D-INFK), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)-Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)
Subjects: Rotation period, 010504 meteorology & atmospheric sciences, Brown dwarf, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Rotation, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Absorption (logic), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], PSO J318.5-22, Astronomy and Astrophysics, Spectral bands, Amplitude, 13. Climate action, Space and Planetary Science, astro-ph.EP, Astrophysics::Earth and Planetary Astrophysics, Planetary mass, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present simultaneous HST WFC3 + Spitzer IRAC variability monitoring for the highly-variable young ($\sim$20 Myr) planetary-mass object PSO J318.5-22. Our simultaneous HST + Spitzer observations covered $\sim$2 rotation periods with Spitzer and most of a rotation period with HST. We derive a period of 8.6$\pm$0.1 hours from the Spitzer lightcurve. Combining this period with the measured $v sin i$ for this object, we find an inclination of 56.2$\pm 8.1^{\circ}$. We measure peak-to-trough variability amplitudes of 3.4$\pm$0.1$\%$ for Spitzer Channel 2 and 4.4 - 5.8$\%$ (typical 68$\%$ confidence errors of $\sim$0.3$\%$) in the near-IR bands (1.07-1.67 $\mu$m) covered by the WFC3 G141 prism -- the mid-IR variability amplitude for PSO J318.5-22 one of the highest variability amplitudes measured in the mid-IR for any brown dwarf or planetary mass object. Additionally, we detect phase offsets ranging from 200--210$^{\circ}$ (typical error of $\sim$4$^{\circ}$) between synthesized near-IR lightcurves and the Spitzer mid-IR lightcurve, likely indicating depth-dependent longitudinal atmospheric structure in this atmosphere. The detection of similar variability amplitudes in wide spectral bands relative to absorption features suggests that the driver of the variability may be inhomogeneous clouds (perhaps a patchy haze layer over thick clouds), as opposed to hot spots or compositional inhomogeneities at the top-of-atmosphere level., Comment: 48 pages, 22 figures, accepted to AJ
Published: 2018

47. New spectro-photometric characterization of the substellar object HR 2562 B using SPHERE

Author: S. Scuderi, Mickael Bonnefoy, Bernardo Salasnich, Maud Langlois, Luigi Lessio, Eric Lagadec, V. De Caprio, Gael Chauvin, G. Farisato, Arthur Vigan, E. Sissa, Daniela Fantinel, C. Lazzoni, Alice Zurlo, Enrico Giro, Massimo Turatto, Markus Feldt, Raffaele Gratton, Silvano Desidera, Benjamin Charnay, S. Incorvaia, Markus Janson, Andrea Baruffolo, A. M. Lagrange, Dino Mesa, Jean-Loup Baudino, Janis Hagelberg, Jacopo Antichi, Enrico Cascone, Riccardo Claudi, Anne-Lise Maire, Anthony Boccaletti, P. Delorme, Valentina D'Orazi, Patrick Bruno, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), University of Oxford, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Claude Bernard Lyon 1 - Faculté des sciences (UCBL FS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Stockholm Observatory Department of Astronomy, Stockholm University, INAF - Osservatorio Astrofisico di Arcetri (OAA), Max-Planck-Institut für Mikrostrukturphysik (MPI-HALLE), INAF - Osservatorio Astronomico di Capodimonte (OAC), Istituto di Astrofisica Spaziale e Fisica Cosmica - Milano (IASF-MI), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Catania (OACT), University of Oxford [Oxford], PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 - Faculté des sciences et technologies (UCBL FST), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF-Osservatorio Astronomico di Padova, Department of Physics, University of Oxford, Oxford, UK, Pôle Planétologie du LESIA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Nucleo de Astronomia, Facultad de Ingenieria, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile, INAF Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123, Catania, Italy, Osservatorio Astronomico di Cagliari, Astrochemistry Group (INAF), Laboratoire Franco-Chilien d'Astronomie, UMI 3386, INAF - Osservatorio Astronomico di Brera (OAB), Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)
Subjects: 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, Star (graph theory), 01 natural sciences, 0103 physical sciences, Gemini Planet Imager, Substellar object, 010303 astronomy & astrophysics, planetary systems, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, instrumentation: spectrographs, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], stars: late-type, Astronomy and Astrophysics, Planetary system, methods: data analysis, Characterization (materials science), Space and Planetary Science, [SDU]Sciences of the Universe [physics], techniques: imaging spectroscopy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: HR2562 is an F5V star located at ~33 pc from the Sun hosting a substellar companion that was discovered using the GPI instrument. The main objective of the present paper is to provide an extensive characterisation of the substellar companion, by deriving its fundamental properties. We observed HR 2562 with the near-infrared branch (IFS and IRDIS) of SPHERE at the VLT. During our observations IFS was operating in the YJ band, while IRDIS was observing with the $H$ broad-band filter. The data were reduced with the dedicated SPHERE GTO pipeline, which is custom-designed for this instrument. On the reduced images, we then applied the post-processing procedures that are specifically prepared to subtract the speckle noise. The companion is clearly detected in both IRDIS and IFS datasets. We obtained photometry in three different spectral bands. The comparison with template spectra allowed us to derive a spectral type of T2-T3 for the companion. Using both evolutionary and atmospheric models we inferred the main physical parameters of the companion obtaining a mass of 32+/-14$~MJup, T_{eff}=1100+/-200 K and log(g)=4.75+/-0.41., Comment: 12 pages, 11 figures, Accepted by A&A
Published: 2018

48. Orbital and atmospheric characterization of the planet within the gap of the PDS 70 transition disk

Author: Anne-Lise Maire, Hervé Beust, Th. Henning, Daniel Rouan, Anthony Boccaletti, Alice Zurlo, Jean-Loup Baudino, Janis Hagelberg, Francois Menard, N. Pawellek, Benjamin Charnay, Karan Molaverdikhani, P. Mollière, Faustine Cantalloube, Maud Langlois, Gael Chauvin, L. Weber, Myriam Benisty, Zahed Wahhaj, Eric Stadler, E. Sissa, Anthony Cheetham, Michael Meyer, Matthias Samland, M. Feldt, André Müller, R. van Boekel, Miriam Keppler, Z. C. Long, Dino Mesa, M. Bonnefoy, R. Ligi, Christoph Mordasini, C. Lazzoni, Joany Andreina Manjarres Ramos, R. G. Gratton, Julien Girard, Thierry Fusco, Arthur Vigan, A. Pavlov, Sascha P. Quanz, Anne-Marie Lagrange, Thibaut Moulin, M. Gennaro, Silvano Desidera, Markus Janson, Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Universidad de Santiago de Chile [Santiago] (USACH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of Oxford [Oxford], Space Telescope Science Institute (STSci), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Institute for Particle Physics and Astrophysics [ETH Zürich] (IPA), Department of Physics [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Stockholm University, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), INAF - Osservatorio Astronomico di Brera (OAB), Instituto de Astronomia y ciencias Planetarias de Atacama (INCT), Universidad de Atacama, University of Michigan [Ann Arbor], University of Michigan System, Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Universität Bern [Bern], Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Universidad Diego Portales [Santiago] (UDP), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)-Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Pawellek, Nicole [0000-0002-9385-9820], Apollo - University of Cambridge Repository, University of Oxford, Université de Genève = University of Geneva (UNIGE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Universiteit Leiden, Universität Bern [Bern] (UNIBE), ANR-16-CE31-0013,PLANET-FORMING-DISKS,De meilleurs modèles pour de meilleures données(2016), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Laboratoire Franco-Chilien d'Astronomie, UMI 3386, Pôle Planétologie du LESIA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Department of Physics, University of Oxford, Oxford, UK, Space Telescope Science Institute (STScI), Geneva Observatory, University of Geneva, Chemin des Mailettes 51, 1290, Versoix, Switzerland, INAF-Osservatorio Astronomico di Padova, ONERA, Institute for Astronomy, Department of Physics, ETH Zürich, INAF-Osservatorio Astronomico di Brera (INAF-OAB), Leiden Observatory, Physikalisches Institut, Universitat Bern, Gesellschaftsstrasse 6, 3012, Bern, Switzerland, European Southern Observatory, and Nucleo de Astronomia, Facultad de Ingenieria y Ciencias, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile
Subjects: 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, Planet, 0103 physical sciences, planets and satellites: individual: PDS 70, Astrophysics::Solar and Stellar Astrophysics, Circular orbit, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, planets and satellites: atmospheres, Earth and Planetary Astrophysics (astro-ph.EP), Atmospheric models, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Astrometry, Orbit, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Orbital motion, Spectral energy distribution, astrometry, Astrophysics::Earth and Planetary Astrophysics, methods: observational, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], techniques: spectroscopic, Astrophysics - Earth and Planetary Astrophysics
Abstract: Aims: We aim to characterize the orbital and atmospheric properties of PDS 70 b, which was first identified on May 2015 in the course of the SHINE survey with SPHERE, the extreme adaptive-optics instrument at the VLT. Methods: We obtained new deep SPHERE/IRDIS imaging and SPHERE/IFS spectroscopic observations of PDS 70 b. The astrometric baseline now covers 6 years which allows us to perform an orbital analysis. For the first time, we present spectrophotometry of the young planet which covers almost the entire near-infrared range (0.96 to 3.8 micrometer). We use different atmospheric models covering a large parameter space in temperature, log(g), chemical composition, and cloud properties to characterize the properties of the atmosphere of PDS 70 b. Results: PDS 70 b is most likely orbiting the star on a circular and disk coplanar orbit at ~22 au inside the gap of the disk. We find a range of models that can describe the spectrophotometric data reasonably well in the temperature range between 1000-1600 K and log(g) no larger than 3.5 dex. The planet radius covers a relatively large range between 1.4 and 3.7 R_jupiter with the larger radii being higher than expected from planet evolution models for the age of the planet of 5.4 Myr. Conclusions: This study provides a comprehensive dataset on the orbital motion of PDS 70 b, indicating a circular orbit and a motion coplanar with the disk. The first detailed spectral energy distribution of PDS 70 b indicates a temperature typical for young giant planets. The detailed atmospheric analysis indicates that a circumplanetary disk may contribute to the total planet flux., Comment: accepted for publication in A&A (10 pages, 8 figures)
Published: 2018
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49. In-depth study of moderately young but extremely red, very dusty substellar companion HD 206893B

Author: Olivier Absil, Anne-Marie Lagrange, Alice Zurlo, Franz-Josef Hambsch, J. L. Beuzit, P. W. Lucas, C. Petit, Th. Henning, Anne-Lise Maire, Mickael Bonnefoy, Daniel Rouan, Norbert Hubin, T. Schmidt, Francois Wildi, Christian Ginski, L. Rodet, Julien Milli, Joshua E. Schlieder, Mariangela Bonavita, Johan Olofsson, A. Pavlov, Valentina D'Orazi, Joseph C. Carson, C. Mordasini, Anthony Cheetham, Elvira Covino, Janis Hagelberg, Raphaël Galicher, Julien Girard, Baptiste Lavie, Valentin Christiaens, M. Feldt, Anthony Boccaletti, Gael Chauvin, David Mouillet, C. Lazzoni, Federico Marocco, Stéphane Udry, Benjamin Charnay, Sergio Messina, Silvano Desidera, Arthur Vigan, Ronald Roelfsema, R. G. Gratton, A. Delboulbe, Beth Biller, Faustine Cantalloube, Maud Langlois, V. De Caprio, Philippe Delorme, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Leiden Observatory [Leiden], Universiteit Leiden, Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Departamento de Astronomía, Universidad de Chile = University of Chile [Santiago] (UCHILE), Millenium Nucleus Protoplanetary Disks in ALMA Early Science, Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, INAF - Osservatorio Astrofisico di Catania (OACT), Monash University [Melbourne], European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, NASA ExoPlanet Science Institute (NExScI), California Institute of Technology (CALTECH), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), SUPA, Institute for Astronomy, University of Edinburgh, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), Universidad Diego Portales [Santiago] (UDP), Instituto de Fisica y Astronomia [Valparaiso], Universidad de Valparaiso [Chile], DAAA, ONERA, Université Paris-Saclay [Châtillon], ONERA-Université Paris-Saclay, Remote Observatory Atacama Desert (ROAD), Arizona Materials Laboratory (AML), University of Arizona, Centre for Astrophysics Research [Hatfield], University of Hertfordshire [Hatfield] (UH), College of Charleston, INAF - Osservatorio Astronomico di Capodimonte (OAC), NOVA Optical Infrared Instrumentation Group, ANR-14-CE33-0018,GIPSE,Exploration des planetes géantes extrasolaires(2014), ANR-10-LABX-0056,OSUG@2020,Innovative strategies for observing and modelling natural systems(2010), European Project: 226604,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2008-1,OPTICON(2009), European Project: 312430,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2012-1-RTD,OPTICON(2013), European Project: 337569,EC:FP7:ERC,ERC-2013-StG,VORTEX(2013), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Universiteit Leiden [Leiden], Universidad de Chile, Universität Bern [Bern], Université de Genève (UNIGE), Instituto de Fisica y Astronomia, ONERA - The French Aerospace Lab [Châtillon], ONERA, Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, INAF-Osservatorio Astronomico di Padova, Leiden Observatory, University of Liège, INAF-Osservatorio Astrofisico di Catania (INAF-OACt), European Southern Observatory, Institute for Astronomy, The University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK, ISDC, Geneva Observatory, University of Geneva, Nucleo de Astronomia, Facultad de Ingenieria, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile, Remote Observatory Atacama Desert (ROAD), Vereniging Voor Sterrenkunde (VVS), Oude Bleken 12, 2400, Mol, Belgium, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Bern (UBERN), Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Institute for Astronomy, Blackford Hill, INAF Napoli: INAF, Astrophysical Observatory of Capodimonte, Salita Moiariello 16, 80131, Napoli, Italy, Netherlands Institute for Radio Astronomy (ASTRON), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)
Subjects: 010504 meteorology & atmospheric sciences, 530 Physics, Brown dwarf, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, planets and satellites: atmospheres, planet-disk interactions, 520 Astronomy, techniques: high angular resolution, Astronomy and Astrophysics, 500 Science, 620 Engineering, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], brown dwarfs
Abstract: The substellar companion HD206893b has recently been discovered by direct imaging of its disc-bearing host star with the SPHERE instrument. We investigate the atypical properties of the companion, which has the reddest near-infrared colours among all known substellar objects, either orbiting a star or isolated, and we provide a comprehensive characterisation of the host star-disc-companion system. We conducted a follow-up of the companion with adaptive optics imaging and spectro-imaging with SPHERE, and a multiinstrument follow-up of its host star. We obtain a R=30 spectrum from 0.95 to 1.64 micron of the companion and additional photometry at 2.11 and 2.25 micron. We carried out extensive atmosphere model fitting for the companions and the host star in order to derive their age, mass, and metallicity. We found no additional companion in the system in spite of exquisite observing conditions resulting in sensitivity to 6MJup (2MJup) at 0.5" for an age of 300 Myr (50 Myr). We detect orbital motion over more than one year and characterise the possible Keplerian orbits. We constrain the age of the system to a minimum of 50 Myr and a maximum of 700 Myr, and determine that the host-star metallicity is nearly solar. The comparison of the companion spectrum and photometry to model atmospheres indicates that the companion is an extremely dusty late L dwarf, with an intermediate gravity (log g 4.5-5.0) which is compatible with the independent age estimate of the system. Though our best fit corresponds to a brown dwarf of 15-30 MJup aged 100-300 Myr, our analysis is also compatible with a range of masses and ages going from a 50 Myr 12MJup planetary-mass object to a 50 MJup Hyades-age brown dwarf..., Comment: Accepted to A&A
Published: 2017

50. Evolution of Titan’s atmosphere during the Late Heavy Bombardment

Author: Olivier Grasset, S. Carpy, Julien Monteux, Benjamin Charnay, Gabriel Tobie, Nadejda Marounina, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV), Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Virtual Planetary Laboratory [Seattle] (VPL), NASA Astrobiology Institute (NAI), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), and Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Population, [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography, Atmospheric sciences, 01 natural sciences, Astrobiology, symbols.namesake, evolution, 0103 physical sciences, Atmosphere of Titan, education, 010303 astronomy & astrophysics, Late Heavy Bombardment, 0105 earth and related environmental sciences, education.field_of_study, Atmosphere, Impact processes, Astronomy and Astrophysics, Crust, High surface, Outgassing, 13. Climate action, Space and Planetary Science, symbols, Environmental science, Titan, Titan (rocket family), Mass fraction
Abstract: The mass and composition of Titan’s massive atmosphere, which is dominated by N2 and CH4 at present, have probably varied all along its history owing to a combination of exogenous and endogenous processes. In the present study, we investigate its fate during the Late Heavy Bombardment (LHB) by modeling the competitive loss and supply of volatiles by cometary impacts and their consequences on the atmospheric balance. For surface albedos ranging between 0.1 and 0.7, we examine the emergence of an atmosphere during the LHB as well as the evolution of a primitive atmosphere with various masses and compositions prior to this event, accounting for impact-induced crustal NH3–N2 conversion and subsequent outgassing as well as impact-induced atmospheric erosion. By considering an impactor population characteristic of the LHB, we show that the generation of a N2-rich atmosphere with a mass equivalent to the present-day one requires ammonia mass fraction of 2–5%, depending on surface albedos, in an icy layer of at least 50 km below the surface, implying an undifferentiated interior at the time of LHB. Except for high surface albedos ( A S ⩾ 0.7 ) where most of the released N2 remain frozen at the surface, our calculations indicate that the high-velocity impacts led to a strong atmospheric erosion. For a differentiated Titan with a thin ammonia-enriched crust (⩽5 km) and A S 0.6 , any atmosphere preexisting before the LHB should be more than 5 times more massive than at present, in order to sustain an atmosphere equivalent to the present-day one. This implies that either a massive atmosphere was formed on Titan during its accretion or that the nitrogen-rich atmosphere was generated after the LHB.
Published: 2015

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