The stable climate of KELT-9b
Journal
Date Issued
2022
Author(s)
Jones, K.
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Morris, B. M.
•
Demory, B. O.
•
Heng, K.
•
Hooton, M. J.
•
Billot, N.
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Ehrenreich, D.
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Hoyer, S.
•
Simon, A. E.
•
Lendl, M.
•
Demangeon, O. D.S.
•
Sousa, S. G.
•
Bonfanti, A.
•
Wilson, T. G.
•
Salmon, S.
•
Csizmadia, Sz
•
Parviainen, H.
•
•
Alibert, Y.
•
Alonso, R.
•
Anglada, G.
•
Bárczy, T.
•
Barrado, D.
•
Barros, S. C.C.
•
Baumjohann, W.
•
Beck, M.
•
Beck, T.
•
Benz, W.
•
Bonfils, X.
•
Brandeker, A.
•
Broeg, C.
•
Cabrera, J.
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Charnoz, S.
•
Collier Cameron, A.
•
Davies, M. B.
•
Deleuil, M.
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Deline, A.
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Delrez, L.
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Erikson, A.
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Fortier, A.
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Fossati, L.
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Fridlund, M.
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Gandolfi, D.
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Gillon, M.
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Güdel, M.
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Isaak, K. G.
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Kiss, L. L.
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Laskar, J.
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Lecavelier Des Etangs, A.
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Lovis, C.
•
•
Maxted, P. F.L.
•
•
Olofsson, G.
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Ottensamer, R.
•
•
Pallé, E.
•
Peter, G.
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Piotto, G.
•
Pollacco, D.
•
Queloz, D.
•
•
Rando, N.
•
Ratti, F.
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Rauer, H.
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Reimers, C.
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Ribas, I.
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Santos, N. C.
•
•
Ségransan, D.
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Smith, A. M.S.
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Steller, M.
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Szabó, Gy M.
•
Thomas, N.
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Udry, S.
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Van Grootel, V.
•
Walter, I.
•
Walton, N. A.
•
Wang Jungo, W.
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. We find no evidence of variability of the brightness temperature of the planet, excluding variability greater than 1%
Volume
666
Start page
A118
Issn Identifier
0004-6361
Rights
open.access
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