Asymmetry in the atmosphere of the ultra-hot Jupiter WASP-76 b

Article Article scientifique Article Asymmetry in the atmosphere of the ultra-hot Jupiter WASP-76 b eng 2024-04-05 2024-04-05 author Demangeon Olivier D.S. 0000-0001-7918-0355 author Cubillos P.E. author Singh Vikash 0000-0002-7485-6309 author Wilson Thomas G. 0000-0001-8749-1962 author Carone L. author Bekkelien Anja 0000-0003-3778-3427 717636 Département d'astronomie (ASTRO) author Deline Adrien 797061 Département d'astronomie (ASTRO) author Ehrenreich David 0000-0001-9704-5405 789146 Département d'astronomie (ASTRO) author Maxted Pierre F.L. 0000-0003-3794-1317 author Demory Brice-Olivier 0000-0002-9355-5165 629568 author Zingales Tiziano 0000-0001-6880-5356 author Lendl Monika 0000-0001-9699-1459 715612 Département d'astronomie (ASTRO) author Bonfanti Andrea 0000-0002-1916-5935 author Sousa Sérgio G. 0000-0001-9047-2965 author Brandeker Alexis 0000-0002-7201-7536 author Alibert Yann 0000-0002-4644-8818 author Alonso Sobrino Roi 0000-0001-8462-8126 690729 author Asquier J. author Bárczy Tamás 0000-0002-7822-4413 author Navascues David Barrado 0000-0002-5971-9242 author Barros Susana 0000-0003-2434-3625 511367 author Baumjohann Wolfgang 0000-0001-6271-0110 author Beck Mathias 0000-0003-3926-0275 133384 author Beck T. author Benz Willy 0000-0001-7896-6479 93881 author Billot Nicolas 0000-0003-3429-3836 861787 Département d'astronomie (ASTRO) author Biondi Federico 0000-0002-1337-3653 author Borsato Luca 0000-0003-0066-9268 author Broeg Christopher 0000-0001-5132-2614 author Buder M. author Collier Cameron Andrew 0000-0002-8863-7828 author Csizmadia Szilard 0000-0001-6803-9698 author Davies Melvyn B. 0000-0001-6080-1190 author Deleuil Magali 0000-0001-6036-0225 author Delrez Laetitia 0000-0001-6108-4808 932714 author Erikson A. author Fortier Andrea 0000-0001-8450-3374 author Fossati Luca 0000-0003-4426-9530 author Fridlund Malcolm 0000-0002-0855-8426 author Gandolfi Davide 0000-0001-8627-9628 author Gillon Michael 0000-0003-1462-7739 642673 author Güdel Manuel 0000-0001-9818-0588 author Günther Maximilian N. 0000-0002-3164-9086 author Heitzmann Alexis 0000-0002-8091-7526 415715 Département d'astronomie (ASTRO) author Helling Ch. author Hoyer Sergio 0000-0003-3477-2466 author Isaak Kate G. 0000-0001-8585-1717 author Kiss Laszlo L. 0000-0002-3234-1374 author Lam Kristine Wai Fun 0000-0002-9910-6088 author Laskar Jacques 0000-0003-2634-789X author Lecavelier des Etangs Alain 0000-0002-5637-5253 author Magrin Demetrio 0000-0003-0312-313X author Mecina Marko 0000-0002-3258-7526 author Mordasini Christoph 0000-0002-1013-2811 author Nascimbeni Valerio 0000-0001-9770-1214 author Olofsson Göran 0000-0003-3747-7120 author Ottensamer R. author Pagano Isabella 0000-0001-9573-4928 author Pallé Enric 0000-0003-0987-1593 author Peter Gisbert 0000-0001-6101-2513 author Piotto Giampaolo 0000-0002-9937-6387 author Pollacco D. author Queloz Didier 0000-0002-3012-0316 27139 author Ragazzoni Roberto 0000-0002-7697-5555 author Rando N. author Rauer Heike 0000-0002-6510-1828 author Ribas Ignasi 0000-0002-6689-0312 author Rieder M. author Salmon Sébastien 0000-0002-1714-3513 936024 author Santos Nuno 0000-0003-4422-2919 514095 author Scandariato Gaetano 0000-0003-2029-0626 author Segransan Damien 0000-0003-2355-8034 134301 Département d'astronomie (ASTRO) author Simon Attila E. 0000-0001-9773-2600 author Smith Alexis M.S. 0000-0002-2386-4341 author Stalport Manu Denis 0000-0003-0996-6402 884893 author Szabó Gyula M. 0000-0002-0606-7930 author Thomas N. author Udry Stéphane 0000-0001-7576-6236 23409 Département d'astronomie (ASTRO) author Van Grootel Valerie 0000-0003-2144-4316 author Venturini Julia 0000-0001-9527-2903 984012 Département d'astronomie (ASTRO) author Villaver E. author Walton Nicholas A. 0000-0003-3983-8778 1-35 A27 10.1051/0004-6361/202348270 0004-6361 https://www.aanda.org/10.1051/0004-6361/202348270 Context: WASP-76 b has been a recurrent subject of study since the detection of a signature in high-resolution transit spectroscopy data indicating an asymmetry between the two limbs of the planet. The existence of this asymmetric signature has been confirmed by multiple studies, but its physical origin is still under debate. In addition, it contrasts with the absence of asymmetry reported in the infrared (IR) phase curve. Aims: We provide a more comprehensive dataset of WASP-76 b with the goal of drawing a complete view of the physical processes at work in this atmosphere. In particular, we attempt to reconcile visible high-resolution transit spectroscopy data and IR broadband phase curves. Methods: We gathered 3 phase curves, 20 occultations, and 6 transits for WASP-76 b in the visible with the CHEOPS space telescope. We also report the analysis of three unpublished sectors observed by the TESS space telescope (also in the visible), which represents 34 phase curves. Results: WASP-76 b displays an occultation of 260 ± 11 and 152 ± 10 ppm in TESS and CHEOPS bandpasses respectively. Depending on the composition assumed for the atmosphere and the data reduction used for the IR data, we derived geometric albedo estimates that range from 0.05 ± 0.023 to 0.146 ± 0.013 and from <0.13 to 0.189 ± 0.017 in the CHEOPS and TESS bandpasses, respectively. As expected from the IR phase curves, a low-order model of the phase curves does not yield any detectable asymmetry in the visible either. However, an empirical model allowing for sharper phase curve variations offers a hint of a flux excess before the occultation, with an amplitude of ~40 ppm, an orbital offset of ~ −30°, and a width of ~20º. We also constrained the orbital eccentricity of WASP-76 b to a value lower than 0.0067, with a 99.7% confidence level. This result contradicts earlier proposed scenarios aimed at explaining the asymmetry observed in high-resolution transit spectroscopy. Conclusions: In light of these findings, we hypothesise that WASP-76 b could have night-side clouds that extend predominantly towards its eastern limb. At this limb, the clouds would be associated with spherical droplets or spherically shaped aerosols of an unknown species, which would be responsible for a glory effect in the visible phase curves. Techniques: photometric Planets and satellites: atmospheres Planets and satellites: composition Dewey 520 Fundação para a Ciência e a Tecnologia, I.P. Characterisation of Earth-size transiting planets IF/01312/2014/CP1215/CT0004 IF/01312/2014/CP1215/CT0004 PT Investigador FCT UK Research and Innovation Astronomy at St Andrews 2018-2021 ST/R000824/1 GB STFC UK Research and Innovation Astronomy at St Andrews 2021 - 2024 ST/V000861/1 GB STFC Fundação para a Ciência e a Tecnologia, I.P. Institute of Astrophysics and Space Sciences UIDP/04434/2020 IA PT 6817 - DCRRNI ID European Commission Alexander von Humboldt and the Globalization of Science: Networks of Knowledge between Germany and the United States in the 19th Century 327127 AHUMSCIENCENET EU FP7 Fundação para a Ciência e a Tecnologia, I.P. Star-exoplanet compositional link: towards realistic characterization of terrestrial planets 2022.06962.PTDC EXO-TERRA PT 3599-PPCDT UK Research and Innovation Astrophysics at Keele: planets, stars and galaxies. ST/M001040/1 GB STFC European Commission FInding ExoeaRths: tackling the ChallengEs of stellar activity 101052347 FIERCE EU HE Fundação para a Ciência e a Tecnologia, I.P. Institute of Astrophysics and Space Sciences UIDB/04434/2020 IA PT 6817 - DCRRNI ID European Commission Virtual Laboratories for Exoplanets and Planet Forming Disks 860470 CHAMELEON EU H2020 European Commission Future of upper atmospheric characterisation of exoplanets with spectroscopy 724427 FOUR ACES EU H2020 26 Département d'astronomie 12 false Astronomy & astrophysics 684 b99c05fb-cf94-4501-83a8-c361493b9d1b Article (Published version) Public aa48270-23.pdf 15407802 application/pdf CC BY-4.0 a230ff5bdd61c75aae8b92edc95ace88fa5c1391c51bac885554524799e13e2d openAccess Faculté des sciences / Département d'astronomie

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