The atmosphere and architecture of WASP-189 b probed by its CHEOPS phase curve
Artikel i vetenskaplig tidskrift, 2022
Context. Gas giants orbiting close to hot and massive early-type stars can reach dayside temperatures that are comparable to those of the coldest stars. These 'ultra-hot Jupiters' have atmospheres made of ions and atomic species from molecular dissociation and feature strong day-to-night temperature gradients. Photometric observations at different orbital phases provide insights on the planet's atmospheric properties. Aims. We aim to analyse the photometric observations of WASP-189 acquired with the Characterising Exoplanet Satellite (CHEOPS) to derive constraints on the system architecture and the planetary atmosphere. Methods. We implemented a light-curve model suited for an asymmetric transit shape caused by the gravity-darkened photosphere of the fast-rotating host star. We also modelled the reflective and thermal components of the planetary flux, the effect of stellar oblateness and light-travel time on transit-eclipse timings, the stellar activity, and CHEOPS systematics. Results. From the asymmetric transit, we measure the size of the ultra-hot Jupiter WASP-189 b, R-p = 1.600(-0.016)(+0.017)R(J), with a precision of 1%, and the true orbital obliquity of the planetary system, Psi(P) = 89.6 +/- 1.2 deg (polar orbit). We detect no significant hotspot offset from the phase curve and obtain an eclipse depth of delta ecl = 96.5(-5.9)(+4).(5) ppm, from which we derive an upper limit on the geometric albedo: A(g) < 0.48. We also find that the eclipse depth can only be explained by thermal emission alone in the case of extremely inefficient energy redistribution. Finally, we attribute the photometric variability to the stellar rotation, either through superficial inhomogeneities or resonance couplings between the convective core and the radiative envelope. Conclusions. Based on the derived system architecture, we predict the eclipse depth in the upcoming Transiting Exoplanet Survey Satellite (TESS) observations to be up to similar to 165 ppm. High-precision detection of the eclipse in both CHEOPS and TESS passbands might help disentangle reflective and thermal contributions. We also expect the right ascension of the ascending node of the orbit to precess due to the perturbations induced by the stellar quadrupole moment J(2) (oblateness).
planets and satellites: individual: WASP-189 b
planets and satellites: atmospheres
techniques: photometric
Författare
A. Deline
Université de Genève
M. J. Hooton
Universität Bern
M. Lendl
Université de Genève
B. Morris
Universität Bern
S. Salmon
Université de Genève
G. Olofsson
Stockholms universitet
C. Broeg
Universität Bern
D. Ehrenreich
Université de Genève
M. Beck
Université de Genève
A. Brandeker
Stockholms universitet
S. Hoyer
Aix-Marseille Université
S. Sulis
Aix-Marseille Université
V. Van Grootel
Universite de Liège
V Bourrier
Université de Genève
O. Demangeon
Universidade do Porto
B-O Demory
Universität Bern
K. Heng
Ludwig-Maximilians-Universität München (LMU)
Universität Bern
The University of Warwick
H. Parviainen
Instituto de Astrofísica de Canarias
Universidad de la Laguna
L. M. Serrano
Universita degli Studi di Torino
V Singh
Istituto nazionale di astrofisica (INAF)
A. Bonfanti
Österreichische Akademie der Wissenschaften
L. Fossati
Österreichische Akademie der Wissenschaften
D. Kitzmann
Universität Bern
S. G. Sousa
Universidade do Porto
T. G. Wilson
University of St Andrews
Y. Alibert
Universität Bern
R. Alonso
Universidad de la Laguna
Instituto de Astrofísica de Canarias
G. Anglada
Consejo Superior de Investigaciones Científicas (CSIC)
T. Barczy
Admatis
D. Barrado Navascues
Centro de Astrobiología (INTA-CSIC)
S. C. C. Barros
Universidade do Porto
W. Baumjohann
Österreichische Akademie der Wissenschaften
T. Beck
Universität Bern
A. Bekkelien
Université de Genève
W. Benz
Universität Bern
N. Billot
Université de Genève
X. Bonfils
Université Grenoble Alpes
J. Cabrera
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
S. Charnoz
Université Paris Descartes
A. Collier Cameron
University of St Andrews
C. Corral van Damme
Europeiska rymdorganisationen (ESA)
Sz Csizmadia
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
M. B. Davies
Lunds universitet
M. Deleuil
Aix-Marseille Université
L. Delrez
Universite de Liège
T. de Roche
Universität Bern
A. Erikson
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
A. Fortier
Universität Bern
Malcolm Fridlund
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
D. Futyan
Université de Genève
D. Gandolfi
Universita degli Studi di Torino
M. Gillon
Universite de Liège
M. Gudel
Universität Wien
P. Gutermann
Aix-Marseille Université
Institut National des Sciences de l'Univers
J. Hasiba
Österreichische Akademie der Wissenschaften
K. G. Isaak
Europeiska rymdorganisationen (ESA)
L. Kiss
Magyar Tudomanyos Akademia
J. Laskar
Sorbonne Université
A. Lecavelier des Etangs
Sorbonne Université
C. Lovis
Université de Genève
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. F. L. Maxted
Keele University
M. Munari
Istituto nazionale di astrofisica (INAF)
V Nascimbeni
Istituto nazionale di astrofisica (INAF)
R. Ottensamer
Universität Wien
I Pagano
Istituto nazionale di astrofisica (INAF)
E. Palle
Instituto de Astrofísica de Canarias
G. Peter
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
G. Piotto
Istituto nazionale di astrofisica (INAF)
Università di Padova
D. Pollacco
The University of Warwick
D. Queloz
Eidgenössische Technische Hochschule Zürich (ETH)
University of Cambridge
R. Ragazzoni
Università di Padova
Istituto nazionale di astrofisica (INAF)
N. Rando
Europeiska rymdorganisationen (ESA)
H. Rauer
Freie Universität Berlin
Technische Universität Berlin
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
I Ribas
Institut d'Estudis Espacials de Catalunya (IEEC)
Consejo Superior de Investigaciones Científicas (CSIC)
N. C. Santos
Universidade do Porto
G. Scandariato
Istituto nazionale di astrofisica (INAF)
D. Segransan
Université de Genève
A. E. Simon
Universität Bern
A. M. S. Smith
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
M. Steller
Österreichische Akademie der Wissenschaften
Gy M. Szabo
Eötvös Loránd University (ELTE)
N. Thomas
Universität Bern
S. Udry
Université de Genève
I Walter
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
N. Walton
University of Cambridge
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 659 A74Ämneskategorier
Astronomi, astrofysik och kosmologi
Atom- och molekylfysik och optik
Den kondenserade materiens fysik
DOI
10.1051/0004-6361/202142400