The stable climate of KELT-9b
Journal article, 2022
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 similar to 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% (1 sigma).
planets and satellites: atmospheres
occultations
planets and satellites: gaseous planets
techniques: photometric
eclipses
instrumentation: photometers
Author
K. Jones
University of Bern
B. M. Morris
University of Bern
B-O Demory
University of Bern
K. Heng
University of Bern
The University of Warwick
M. J. Hooton
University of Bern
University of Cambridge
N. Billot
University of Geneva
D. Ehrenreich
University of Geneva
S. Hoyer
Aix Marseille University
A. E. Simon
University of Bern
M. Lendl
University of Geneva
O. D. S. Demangeon
University of Porto
S. G. Sousa
University of Porto
A. Bonfanti
Austrian Academy of Sciences
T. G. Wilson
University of St Andrews
S. Salmon
University of Geneva
Sz Csizmadia
German Aerospace Center (DLR)
H. Parviainen
Instituto de Astrofísica de Canarias
G. Bruno
Istituto nazionale di astrofisica (INAF)
Y. Alibert
University of Bern
R. Alonso
Instituto de Astrofísica de Canarias
University of La Laguna
G. Anglada
Spanish National Research Council (CSIC)
Institute of Space Studies of Catalonia (IEEC)
T. Barczy
Admatis
D. Barrado
Spanish Astrobiology Center (INTA-CSIC)
S. C. C. Barros
University of Porto
W. Baumjohann
Austrian Academy of Sciences
M. Beck
University of Geneva
T. Beck
University of Bern
W. Benz
University of Bern
X. Bonfils
Grenoble Alpes University
A. Brandeker
Stockholm University
C. Broeg
University of Bern
J. Cabrera
German Aerospace Center (DLR)
S. Charnoz
Paris Descartes University
A. Collier Cameron
University of St Andrews
M. B. Davies
Lund University
M. Deleuil
Aix Marseille University
A. Deline
University of Geneva
L. Delrez
University of Liège
A. Erikson
German Aerospace Center (DLR)
A. Fortier
University of Bern
L. Fossati
Austrian Academy of Sciences
Malcolm Fridlund
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
D. Gandolfi
University of Turin
M. Gillon
University of Liège
M. Gudel
University of Vienna
K. G. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L. L. Kiss
Hungarian Academy of Sciences
Eötvös Loránd University (ELTE)
J. Laskar
Sorbonne University
A. Lecavelier des Etangs
Sorbonne University
C. Lovis
University of Geneva
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. F. L. Maxted
Keele University
V Nascimbeni
Istituto nazionale di astrofisica (INAF)
G. Olofsson
Stockholm University
R. Ottensamer
University of Vienna
I Pagano
Istituto nazionale di astrofisica (INAF)
E. Palle
Instituto de Astrofísica de Canarias
G. Peter
German Aerospace Center (DLR)
G. Piotto
Istituto nazionale di astrofisica (INAF)
University of Padua
D. Pollacco
The University of Warwick
D. Queloz
Swiss Federal Institute of Technology in Zürich (ETH)
University of Cambridge
R. Ragazzoni
University of Padua
Istituto nazionale di astrofisica (INAF)
N. Rando
European Space Agency (ESA)
F. Ratti
European Space Agency (ESA)
H. Rauer
Technische Universität Berlin
Freie Universität Berlin
German Aerospace Center (DLR)
C. Reimers
University of Vienna
I Ribas
Institute of Space Studies of Catalonia (IEEC)
Spanish National Research Council (CSIC)
N. C. Santos
University of Porto
G. Scandariato
Istituto nazionale di astrofisica (INAF)
D. Segransan
University of Geneva
A. M. S. Smith
German Aerospace Center (DLR)
M. Steller
Austrian Academy of Sciences
Gy M. Szabo
Eötvös Loránd University (ELTE)
N. Thomas
University of Bern
S. Udry
University of Geneva
V. Van Grootel
University of Liège
I Walter
German Aerospace Center (DLR)
N. A. Walton
University of Cambridge
W. Wang Jungo
University of Bern
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 666 A118Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Condensed Matter Physics
DOI
10.1051/0004-6361/202243823