CHEOPS geometric albedo of the hot Jupiter HD 209458 b
Journal article, 2022
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 Ag = 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 Ag for any exoplanet. Our calculations of the bandpass-integrated geometric albedo demonstrate that the measured value of Ag 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.
Planetary systems
Planets
Techniques: Photometric
Satellites: Individual: HD 209458 b
Planets and satellites: Atmospheres
Author
A. Brandeker
Stockholm University
Kevin Heng
University of Bern
The University of Warwick
M. Lendl
University of Geneva
J. A. Patel
Stockholm University
Brett M. Morris
University of Bern
C. Broeg
University of Bern
P. Guterman
Laboratoire d'Astrophysique de Marseille
Division Technique INSU
M. Beck
University of Geneva
P. Maxted
Keele University
O. Demangeon
University of Porto
L. Delrez
University of Liège
B.O. Demory
University of Bern
D. Kitzmann
University of Bern
N. C. Santos
University of Porto
V. Singh
Istituto nazionale di astrofisica (INAF)
Y. Alibert
University of Bern
R. Alonso
Instituto de Astrofísica de Canarias
University of La Laguna
G. Anglada
Institute of Space Studies of Catalonia (IEEC)
Institute of Space Sciences (ICE) - CSIC
T. Bárczy
Admatis
D. Barrado
Centro de Astrobiologia (CAB)
S.C.C. Barros
University of Porto
W. Baumjohann
Institut fur Weltraumforschung
T. Beck
University of Bern
W. Benz
University of Bern
N. Billot
University of Geneva
X. Bonfils
Grenoble Alpes University
G. Bruno
University of Bern
J. Cabrera
German Aerospace Center (DLR)
S. Charnoz
Paris Descartes University
A. Collier Cameron
University of St Andrews
C. Corral Van Damme
European Space Research and Technology Centre (ESA ESTEC)
Szilard Csizmadia
German Aerospace Center (DLR)
M. B. Davies
Lund University
M. Deleuil
Laboratoire d'Astrophysique de Marseille
A. Deline
University of Geneva
D. Ehrenreich
University of Geneva
Anders Erikson
German Aerospace Center (DLR)
J. Farinato
Istituto nazionale di astrofisica (INAF)
A. Fortier
University of Bern
L. Fossati
Institut fur Weltraumforschung
Malcolm Fridlund
Leiden University
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
D. Gandolfi
University of Turin
Michaël Gillon
University of Liège
M. Gudel
University of Vienna
S. Hoyer
Laboratoire d'Astrophysique de Marseille
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L.L. Kiss
Eötvös Loránd University (ELTE)
Hungarian Academy of Sciences
J. Laskar
Paris Observatory
A. L. des Etangs
Institut d 'Astrophysique de Paris
C. Lovis
University of Geneva
A. Luntzer
University of Vienna
D. Magrin
Istituto nazionale di astrofisica (INAF)
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
G. Olofsson
Stockholm University
R. Ottensamer
University of Vienna
I. Pagano
Istituto nazionale di astrofisica (INAF)
Enric Palle
Instituto de Astrofísica de Canarias
G. Peter
German Aerospace Center (DLR)
Giampaolo P. Piotto
University of Padua
Istituto nazionale di astrofisica (INAF)
Don L. Pollacco
The University of Warwick
D. Queloz
University of Cambridge
Swiss Federal Institute of Technology in Zürich (ETH)
Roberto Ragazzoni
Istituto nazionale di astrofisica (INAF)
University of Padua
N. Rando
European Space Research and Technology Centre (ESA ESTEC)
H. Rauer
German Aerospace Center (DLR)
Freie Universität Berlin
Technische Universität Berlin
I. Ribas
Institute of Space Studies of Catalonia (IEEC)
Institute of Space Sciences (ICE) - CSIC
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
D. Segransan
University of Geneva
A.E. Simon
University of Bern
Alexis M. S. Smith
German Aerospace Center (DLR)
S. G. Sousa
University of Porto
Manfred B. Steller
Institut fur Weltraumforschung
G.M. Szabó
Eötvös Loránd University (ELTE)
MTA-ELTE Lendület Milky Way Research Group
Nicolas Thomas
University of Bern
S. Udry
University of Geneva
V. Van Grootel
University of Liège
N. A. Walton
University of Cambridge
D. Wolter
German Aerospace Center (DLR)
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 659 L4Subject Categories
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/202243082