The hot dayside and asymmetric transit of WASP-189 b seen by CHEOPS
Journal article, 2020
The CHEOPS space mission dedicated to exoplanet follow-up was launched in December 2019, equipped with the capacity to perform photometric measurements at the 20 ppm level. As CHEOPS carries out its observations in a broad optical passband, it can provide insights into the reflected light from exoplanets and constrain the short-wavelength thermal emission for the hottest of planets by observing occultations and phase curves. Here, we report the first CHEOPS observation of an occultation, namely, that of the hot Jupiter WASP-189 b, a MP ≈ 2MJ planet orbiting an A-type star. We detected the occultation of WASP-189 b at high significance in individual measurements and derived an occultation depth of dF = 87.9 ± 4.3 ppm based on four occultations. We compared these measurements to model predictions and we find that they are consistent with an unreflective atmosphere heated to a temperature of 3435 ± 27 K, when assuming inefficient heat redistribution. Furthermore, we present two transits of WASP-189 b observed by CHEOPS. These transits have an asymmetric shape that we attribute to gravity darkening of the host star caused by its high rotation rate. We used these measurements to refine the planetary parameters, finding a ~25% deeper transit compared to the discovery paper and updating the radius of WASP-189 b to 1.619 ± 0.021RJ. We further measured the projected orbital obliquity to be λ = 86.4-4.4+2.9°, a value that is in good agreement with a previous measurement from spectroscopic observations, and derived a true obliquity of ψ = 85.4 ± 4.3°. Finally, we provide reference values for the photometric precision attained by the CHEOPS satellite: for the V = 6.6 mag star, and using a 1-h binning, we obtain a residual RMS between 10 and 17 ppm on the individual light curves, and 5.7 ppm when combining the four visits.
Planets and satellites: individual: WASP-189 b
Techniques: photometric
Planets and satellites: atmospheres
Author
M. Lendl
University of Geneva
Szilard Csizmadia
German Aerospace Center (DLR)
A. Deline
University of Geneva
L. Fossati
Institut fur Weltraumforschung
D. Kitzmann
University of Bern
Kevin Heng
University of Bern
S. Hoyer
Laboratoire d'Astrophysique de Marseille
S. Salmon
University of Geneva
W. Benz
University of Bern
C. Broeg
University of Bern
D. Ehrenreich
University of Geneva
A. Fortier
University of Bern
D. Queloz
University of Geneva
A. Bonfanti
Institut fur Weltraumforschung
A. Brandeker
Stockholm University
A. Collier Cameron
University of St Andrews
L. Delrez
University of Geneva
A. Garcia Munoz
Technische Universität Berlin
M.J. Hooton
University of Bern
P. Maxted
Keele University
Brett M. Morris
University of Bern
V. Van Grootel
University of Liège
T.G. Wilson
University of St Andrews
Y. Alibert
University of Bern
R. Alonso
Instituto de Astrofísica de Canarias
J. Asquier
European Space Research and Technology Centre (ESA ESTEC)
T. Bandy
University of Bern
T. Bárczy
Admatis
D. Barrado
Centro de Astrobiologia (CAB)
S.C.C. Barros
University of Porto
W. Baumjohann
Institut fur Weltraumforschung
M. Beck
University of Geneva
T. Beck
University of Bern
A. Bekkelien
University of Geneva
M. Bergomi
Istituto nazionale di astrofisica (INAF)
N. Billot
University of Geneva
F. Biondi
Istituto nazionale di astrofisica (INAF)
X. Bonfils
Grenoble Alpes University
V. Bourrier
University of Geneva
M.-D. Busch
University of Bern
J. Cabrera
German Aerospace Center (DLR)
V. Cessa
University of Bern
S. Charnoz
Institut de Physique du Globe de Paris
B. Chazelas
University of Geneva
C. Corral Van Damme
European Space Research and Technology Centre (ESA ESTEC)
Melvyn B. Davies
Lund University
M. Deleuil
Laboratoire d'Astrophysique de Marseille
O. Demangeon
Laboratoire d'Astrophysique de Marseille
B.O. Demory
University of Bern
Anders Erikson
German Aerospace Center (DLR)
J. Farinato
Istituto nazionale di astrofisica (INAF)
Malcolm Fridlund
Leiden University
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
D. Futyan
University of Geneva
D. Gandolfi
Istituto nazionale di astrofisica (INAF)
Michaël Gillon
University of Liège
P. Guterman
Laboratoire d'Astrophysique de Marseille
J. Hasiba
Institut fur Weltraumforschung
E. Hernandez
University of Bern
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L.L. Kiss
Hungarian Academy of Sciences
T. Kuntzer
University of Geneva
A. L. des Etangs
Institut d 'Astrophysique de Paris
T. Lüftinger
University of Vienna
J. Laskar
Paris Observatory
C. Lovis
University of Geneva
D. Magrin
Istituto nazionale di astrofisica (INAF)
L. Malvasio
University of Bern
L. Marafatto
Istituto nazionale di astrofisica (INAF)
H. Michaelis
German Aerospace Center (DLR)
M. Munari
Istituto nazionale di astrofisica (INAF)
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
G. Olofsson
Stockholm University
H. Ottacher
Institut fur Weltraumforschung
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)
D. Piazza
University of Bern
Giampaolo P. Piotto
Istituto nazionale di astrofisica (INAF)
Don L. Pollacco
The University of Warwick
F. Ratti
European Space Research and Technology Centre (ESA ESTEC)
H. Rauer
German Aerospace Center (DLR)
Roberto Ragazzoni
Istituto nazionale di astrofisica (INAF)
N. Rando
European Space Research and Technology Centre (ESA ESTEC)
I. Ribas
Institute of Space Sciences (ICE) - CSIC
M. Rieder
University of Bern
R. Rohlfs
University of Geneva
F. Safa
European Space Research and Technology Centre (ESA ESTEC)
N. C. Santos
University of Porto
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
D. Segransan
University of Geneva
A.E. Simon
University of Bern
V. Singh
Istituto nazionale di astrofisica (INAF)
Alexis M. S. Smith
German Aerospace Center (DLR)
M. Sordet
University of Geneva
S.G. Sousa
University of Porto
Manfred B. Steller
Institut fur Weltraumforschung
G.M. Szabó
Eötvös Loránd University (ELTE)
Nicolas Thomas
University of Bern
M. Tschentscher
German Aerospace Center (DLR)
S. Udry
University of Geneva
V. Viotto
Istituto nazionale di astrofisica (INAF)
I. Walter
German Aerospace Center (DLR)
N. A. Walton
University of Cambridge
F. Wildi
University of Geneva
D. Wolter
German Aerospace Center (DLR)
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 643 202038677Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Other Physics Topics
Roots
Basic sciences
DOI
10.1051/0004-6361/202038677