CHEOPS geometric albedo of the hot Jupiter HD 209458 b

Autor(en): A. Brandeker, K. Heng, M. Lendl, J. A. Patel, B. M. Morris, C. Broeg, P. Guterman, M. Beck, P. F.L. Maxted, O. Demangeon, L. Delrez, B. O. Demory, D. Kitzmann, N. C. Santos, V. Singh, Y. Alibert, R. Alonso, G. Anglada, T. Bárczy, D. Barrado y Navascues, S. C.C. Barros, W. Baumjohann, T. Beck, W. Benz, N. Billot, X. Bonfils, G. Bruno, J. Cabrera, S. Charnoz, A. Collier Cameron, C. Corral van Damme, Sz Csizmadia, M. B. Davies, M. Deleuil, A. Deline, D. Ehrenreich, A. Erikson, J. Farinato, A. Fortier, L. Fossati, M. Fridlund, D. Gandolfi, M. Gillon, M. Güdel, S. Hoyer, K. G. Isaak, L. Kiss, J. Laskar, A. Lecavelier des Etangs, C. Lovis, A. Luntzer, D. Magrin, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, G. Scandariato, D. Ségransan, A. E. Simon, A. M.S. Smith, S. G. Sousa, M. Steller, G. M. Szabó, N. Thomas, S. Udry, V. van Grootel, N. Walton, D. Wolter
Abstrakt: We report the detection of the secondary eclipse of the hot Jupiter HD 209458 b in optical/visible light using the CHEOPS space telescope. Our measurement of 20.4^+3.2_-3.3 parts per million translates into a geometric albedo of A_g = 0.096 ± 0.016. The previously estimated dayside temperature of about 1500 K implies that our geometric albedo measurement consists predominantly of reflected starlight and is largely uncontaminated by thermal emission. This makes the present result one of the most robust measurements of A_g for any exoplanet. Our calculations of the bandpass-integrated geometric albedo demonstrate that the measured value of A_g is consistent with a cloud-free atmosphere, where starlight is reflected via Rayleigh scattering by hydrogen molecules, and the water and sodium abundances are consistent with stellar metallicity. We predict that the bandpass-integrated TESS geometric albedo is too faint to detect and that a phase curve of HD 209458 b observed by CHEOPS would have a distinct shape associated with Rayleigh scattering if the atmosphere is indeed cloud free.
Organisation(en): Institut für Astrophysik
Externe Organisation(en): Stockholm University, Universität Bern, University of Warwick, Universität Genf, Aix-Marseille Université, National Institute for Earth Sciences & Astronomy (INSU-CNRS), Keele University, Universidade do Porto, Université de Liège, INAF - Osservatorio Astronomico di Padova, Instituto de Astrofísica de Canarias (IAC), Universidad de La Laguna, Spanish National Research Council (CSIC), Institut d'Estudis Espacials de Catalunya (IEEC), Admatis, European Space Astronomy Centre (ESA), Österreichische Akademie der Wissenschaften (ÖAW), Université Grenoble-Alpes, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Université Paris VII - Paris-Diderot, University of St. Andrews, European Space Research & Technology Centre (ESA/ESTEC), Lund University, Leiden University, Chalmers University of Technology, Università degli Studi di Torino, MTA Társadalomtudományi Kutatóközpont, Eötvös Loránd University Budapest, Université de recherche Paris Sciences et Lettres, Université Paris VI - Pierre-et-Marie-Curie, INAF-Osservatorio Astrofisico di Catania, Università degli Studi di Padova, University of Cambridge, Eidgenössische Technische Hochschule Zürich, Technische Universität Berlin, Freie Universität Berlin (FU)
Journal: Astronomy and Astrophysics
Band: 659
Anzahl der Seiten: 8
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202243082
Publikationsdatum: 03-2022
Peer-reviewed: Ja
ÖFOS 2012: 103003 Astronomie, 103004 Astrophysik, 103038 Weltraumforschung
Schlagwörter
ASJC Scopus Sachgebiete: Astronomy and Astrophysics, Space and Planetary Science
Link zum Portal: https://ucrisportal.univie.ac.at/de/publications/dd4f2d40-8e19-4a9f-aa88-c27517d34ca4

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