The stable climate of KELT-9b
- Author(s)
- K. Jones, B. M. Morris, B. -O. Demory, K. Heng, M. J. Hooton, N. Billot, D. Ehrenreich, S. Hoyer, A. E. Simon, M. Lendl, O. D. S. Demangeon, S. G. Sousa, A. Bonfanti, T. G. Wilson, S. Salmon, Sz. Csizmadia, H. Parviainen, G. Bruno, Y. Alibert, R. Alonso, G. Anglada, T. Bárczy, D. Barrado, S. C. C. Barros, W. Baumjohann, M. Beck, T. Beck, W. Benz, X. Bonfils, A. Brandeker, C. Broeg, J. Cabrera, S. Charnoz, A. Collier Cameron, M. B. Davies, M. Deleuil, A. Deline, L. Delrez, A. Erikson, A. Fortier, L. Fossati, M. Fridlund, D. Gandolfi, M. Gillon, M. Güdel, K. G. Isaak, L. L. Kiss, J. Laskar, A. Lecavelier des Etangs, C. Lovis, D. Magrin, P. F. L. Maxted, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, F. Ratti, H. Rauer, C. Reimers, I. Ribas, N. C. Santos, G. Scandariato, D. Ségransan, A. M. S. Smith, M. Steller, Gy. M. Szabó, N. Thomas, S. Udry, V. Van Grootel, I. Walter, N. A. Walton, W. Wang Jungo
- Abstract
Even among the most irradiated gas giants, so-called ultra-hot Jupiters, KELT-9b stands out as the hottest planet thus far discovered with a dayside temperature of over 4500 K. At these extreme irradiation levels, we expect an increase in heat redistribution efficiency and a low Bond albedo owed to an extended atmosphere with molecular hydrogen dissociation occurring on the planetary dayside. We present new photometric observations of the KELT-9 system throughout 4 full orbits and 9 separate occultations obtained by the 30 cm space telescope CHEOPS. The CHEOPS bandpass, located at optical wavelengths, captures the peak of the thermal emission spectrum of KELT-9b. In this work we simultaneously analyse CHEOPS phase curves along with public phase curves from TESS and Spitzer to infer joint constraints on the phase curve variation, gravity-darkened transits, and occultation depth in three bandpasses, as well as derive 2D temperature maps of the atmosphere at three different depths. We find a day-night heat redistribution efficiency of ∼0.3 which confirms expectations of enhanced energy transfer to the planetary nightside due to dissociation and recombination of molecular hydrogen. We also calculate a Bond albedo consistent with zero.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Universität Bern, University of Warwick, University of Cambridge, Université de Genève, Aix-Marseille Université, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Universidade do Porto, Österreichische Akademie der Wissenschaften (ÖAW), University of St. Andrews, Institute of Astrophysics of the Canary Islands, INAF-Osservatorio Astrofisico di Catania, University of La Laguna, Spanish National Research Council (CSIC), Institute of Space Studies of Catalonia (IEEC), Admatis Ltd., Université de Paris, Lund University, Université de Liège, Leiden University, Chalmers University of Technology, University of Turin, European Space Agency (ESA), Hungarian Academy of Sciences, Eötvös Loránd University Budapest, Sorbonne Université, Osservatorio Astronomico, Stockholm University, Keele University, University of Padova, Science and Operations Department - Science Division (SCI-SC), Technische Universität Berlin, Freie Universität Berlin (FU), Eidgenössische Technische Hochschule Zürich, University of Grenoble Alpes, Université Paris VI - Pierre-et-Marie-Curie
- Journal
- Astronomy and Astrophysics
- Volume
- 666
- No. of pages
- 19
- ISSN
- 0004-6361
- Publication date
- 10-2022
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy, 103004 Astrophysics
- Keywords
- ASJC Scopus subject areas
- Astronomy and Astrophysics, Space and Planetary Science
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/e3ca8efa-a661-4db2-9c4e-a4669bbc2581