Detection of the tidal deformation of WASP-103b at 3 σ with CHEOPS
Artikel i vetenskaplig tidskrift, 2022
Context. Ultra-short period planets undergo strong tidal interactions with their host star which lead to planet deformation and orbital tidal decay. Aims. WASP-103b is the exoplanet with the highest expected deformation signature in its transit light curve and one of the shortest expected spiral-in times. Measuring the tidal deformation of the planet would allow us to estimate the second degree fluid Love number and gain insight into the planet's internal structure. Moreover, measuring the tidal decay timescale would allow us to estimate the stellar tidal quality factor, which is key to constraining stellar physics. Methods. We obtained 12 transit light curves of WASP-103b with the CHaracterising ExOplanet Satellite (CHEOPS) to estimate the tidal deformation and tidal decay of this extreme system. We modelled the high-precision CHEOPS transit light curves together with systematic instrumental noise using multi-dimensional Gaussian process regression informed by a set of instrumental parameters. To model the tidal deformation, we used a parametrisation model which allowed us to determine the second degree fluid Love number of the planet. We combined our light curves with previously observed transits of WASP-103b with the Hubble Space Telescope (HST) and Spitzer to increase the signal-to-noise of the light curve and better distinguish the minute signal expected from the planetary deformation. Results. We estimate the radial Love number of WASP-103b to be hf = 1.59-0.53+0.45. This is the first time that the tidal deformation is directly detected (at 3 σ) from the transit light curve of an exoplanet. Combining the transit times derived from CHEOPS, HST, and Spitzer light curves with the other transit times available in the literature, we find no significant orbital period variation for WASP-103b. However, the data show a hint of an orbital period increase instead of a decrease, as is expected for tidal decay. This could be either due to a visual companion star if this star is bound, the Applegate effect, or a statistical artefact. Conclusions. The estimated Love number of WASP-103b is similar to Jupiter's. This will allow us to constrain the internal structure and composition of WASP-103b, which could provide clues on the inflation of hot Jupiters. Future observations with James Webb Space Telescope can better constrain the radial Love number of WASP-103b due to their high signal-to-noise and the smaller signature of limb darkening in the infrared. A longer time baseline is needed to constrain the tidal decay in this system.
Planets and satellites: individual: WASP-103b
Planets and satellites: fundamental parameters
Time
Techniques: photometric
Planets and satellites: interiors
Planets and satellites: composition
Författare
S. C.C. Barros
Universidade do Porto
B. Akinsanmi
Université de Genève
Universidade do Porto
G. Boue´
Observatoire de Paris
A. M.S. Smith
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
J. Laskar
Observatoire de Paris
S. Ulmer-Moll
Université de Genève
J. Lillo-Box
Centro de Astrobiologia (CAB)
D. Queloz
University of Cambridge
Université de Genève
A. Collier Cameron
University of St Andrews
S. G. Sousa
Universidade do Porto
D. Ehrenreich
Université de Genève
M.J. Hooton
Universität Bern
G. Bruno
Osservatorio Astrofisico di Catania
B.O. Demory
Universität Bern
A. C.M. Correia
Centre for Physics of the University of Coimbra
O. Demangeon
Universidade do Porto
T.G. Wilson
University of St Andrews
A. Bonfanti
Institut fur Weltraumforschung
S. Hoyer
Aix-Marseille Université
Y. Alibert
Universität Bern
R. Alonso
Universidad de la Laguna
Instituto de Astrofísica de Canarias
G. A. Escudé
Institut de Ciències de l'Espai (ICE) - CSIC
Institut d'Estudis Espacials de Catalunya (IEEC)
D. Barbato
Université de Genève
T. Bárczy
Admatis
D. Barrado
Centro de Astrobiologia (CAB)
W. Baumjohann
Institut fur Weltraumforschung
M. Beck
Université de Genève
T. Beck
Universität Bern
W. Benz
Universität Bern
M. Bergomi
Osservatorio Astronomico di Padova
N. Billot
Université de Genève
X. Bonfils
Université Grenoble Alpes
F. Bouchy
Université de Genève
A. Brandeker
Stockholms universitet
C. Broeg
Universität Bern
J. Cabrera
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
V. Cessa
Universität Bern
S. Charnoz
Université Paris Descartes
C. C.V. Damme
European Space Research and Technology Centre (ESA ESTEC)
M. B. Davies
Lunds universitet
M. Deleuil
Aix-Marseille Université
A. Deline
Université de Genève
L. Delrez
Universite de Liège
Anders Erikson
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
A. Fortier
Universität Bern
L. Fossati
Institut fur Weltraumforschung
Malcolm Fridlund
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Universiteit Leiden
D. Gandolfi
Universita degli Studi di Torino
A. Garciá Muñoz
Technische Universität Berlin
Michaël Gillon
Universite de Liège
M. Gudel
Universität Wien
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
Kevin Heng
The University of Warwick
Universität Bern
L.L. Kiss
Magyar Tudomanyos Akademia
The University of Sydney
A. L. des Etangs
Institut d 'Astrophysique de Paris
M. Lendl
Université de Genève
C. Lovis
Université de Genève
D. Magrin
Osservatorio Astronomico di Padova
Valerio Nascimbeni
Osservatorio Astronomico di Padova
P. Maxted
Keele University
G. Olofsson
Stockholms universitet
R. Ottensamer
Universität Wien
I. Pagano
Osservatorio Astrofisico di Catania
Enric Palle
Universidad de la Laguna
Instituto de Astrofísica de Canarias
H. Parviainen
Universidad de la Laguna
Instituto de Astrofísica de Canarias
G. Peter
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Giampaolo P. Piotto
Università di Padova
Osservatorio Astronomico di Padova
Don L. Pollacco
The University of Warwick
Roberto Ragazzoni
Università di Padova
Osservatorio Astronomico di Padova
N. Rando
European Space Research and Technology Centre (ESA ESTEC)
H. Rauer
Technische Universität Berlin
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Freie Universität Berlin
I. Ribas
Institut de Ciències de l'Espai (ICE) - CSIC
Institut d'Estudis Espacials de Catalunya (IEEC)
N. C. Santos
Universidade do Porto
Gaetano Scandariato
Osservatorio Astrofisico di Catania
D. Segransan
Université de Genève
A.E. Simon
Universität Bern
Manfred B. Steller
Institut fur Weltraumforschung
Gy M. Szabó
Eötvös Loránd University (ELTE)
Nicolas Thomas
Universität Bern
S. Udry
Université de Genève
B. Ulmer
Ingenieurbüro Ulmer - Technische Informatik
V. Van Grootel
Universite de Liège
N. A. Walton
University of Cambridge
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 657 A52Ämneskategorier
Astronomi, astrofysik och kosmologi
DOI
10.1051/0004-6361/202142196