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 A52

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.1051/0004-6361/202142196

Mer information

Senast uppdaterat

2022-02-02