CHEOPS observations confirm nodal precession in the WASP-33 system
Journal article, 2025
Aims. We aim to observe the transits and occultations of WASP-33 b, which orbits a rapidly rotating δ Scuti pulsator, with the goal of measuring the orbital obliquity via the gravity-darkening effect, and constraining the geometric albedo via the occultation depth. Methods. We observed four transits and four occultations with CHEOPS, and employ a variety of techniques to remove the effects of the stellar pulsations from the light curves, as well as the usual CHEOPS systematic effects. We also performed a comprehensive analysis of low-resolution spectral and Gaia data to re-determine the stellar properties of WASP-33. Results. We measure an orbital obliquity 111.3+−00.27 degrees, which is consistent with previous measurements made via Doppler tomography. We also measure the planetary impact parameter, and confirm that this parameter is undergoing rapid secular evolution as a result of nodal precession of the planetary orbit. This precession allows us to determine the second-order fluid Love number of the star, which we find agrees well with the predictions of theoretical stellar models. We are unable to robustly measure a unique value of the occultation depth, and emphasise the need for long-baseline observations to better measure the pulsation periods.
planets and satellites: gaseous planets
planets and satellites: dynamical evolution and stability
planets and satellites: fundamental parameters
stars: oscillations
planets and satellites: individual: WASP-33 b
stars: individual: WASP-33
Author
A. M.S. Smith
German Aerospace Center (DLR)
Szilard Csizmadia
German Aerospace Center (DLR)
V. Van Grootel
University of Liège
M. Lendl
University of Geneva
Carina Persson
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
G. Olofsson
Stockholm University
D. Ehrenreich
University of Geneva
Maximilian N. Günther
European Space Research and Technology Centre (ESA ESTEC)
A. Heitzmann
University of Geneva
S.C.C. Barros
University of Porto
A. Bonfanti
Institut fur Weltraumforschung
A. Brandeker
Stockholm University
J. Cabrera
German Aerospace Center (DLR)
O. Demangeon
University of Porto
L. Fossati
Institut fur Weltraumforschung
J. V. Harre
German Aerospace Center (DLR)
M.J. Hooton
University of Cambridge
S. Hoyer
Laboratoire d'Astrophysique de Marseille
S. Z. Kalman
Eötvös Loránd University (ELTE)
Hungarian Academy of Sciences
S. Salmon
University of Geneva
S.G. Sousa
University of Porto
Gy M. Szabó
Eötvös Loránd University (ELTE)
T.G. Wilson
The University of Warwick
Y. Alibert
University of Bern
Physics Institute
R. Alonso
Instituto de Astrofísica de Canarias
University of La Laguna
J. Asquier
European Space Research and Technology Centre (ESA ESTEC)
T. Bárczy
Admatis
D. Barrado
Centro de Astrobiologia (CAB)
W. Baumjohann
Institut fur Weltraumforschung
W. Benz
University of Bern
Physics Institute
N. Billot
University of Geneva
L. Borsato
Istituto nazionale di astrofisica (INAF)
C. Broeg
Physics Institute
University of Bern
A. Collier Cameron
University of St Andrews
A. Correia
Centre for Physics of the University of Coimbra
P. E. Cubillos
Istituto nazionale di astrofisica (INAF)
Institut fur Weltraumforschung
Melvyn B. Davies
Lund University
M. Deleuil
Laboratoire d'Astrophysique de Marseille
A. Deline
University of Geneva
B.O. Demory
University of Bern
Physics Institute
A. Derekas
Eötvös Loránd University (ELTE)
Billy Edwards
Netherlands Institute for Space Research (SRON)
J. A. Egger
Physics Institute
Anders Erikson
German Aerospace Center (DLR)
A. Fortier
University of Bern
Physics Institute
Malcolm Fridlund
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Leiden University
D. Gandolfi
University of Turin
K. Gazeas
University of Athens
Michaël Gillon
University of Liège
M. Gudel
University of Vienna
J. Hasiba
Institut fur Weltraumforschung
Ch. Helling
Technische Universität Graz
Institut fur Weltraumforschung
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L. L. Kiss
Eötvös Loránd University (ELTE)
Hungarian Academy of Sciences
Judith Korth
Lund University
K. W.F. Lam
German Aerospace Center (DLR)
J. Laskar
Paris Observatory
A. L. des Etangs
Institut d 'Astrophysique de Paris
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. Maxted
Keele University
Bruno Merín
European Space Astronomy Centre (ESAC)
C. Mordasini
Physics Institute
University of Bern
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
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)
D. Piazza
University of Bern
Giampaolo P. Piotto
University of Padua
Istituto nazionale di astrofisica (INAF)
Don L. Pollacco
D. Queloz
Swiss Federal Institute of Technology in Zürich (ETH)
University of Cambridge
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
I. Ribas
Institute of Space Sciences (ICE) - CSIC
Institute of Space Studies of Catalonia (IEEC)
N. C. Santos
University of Porto
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
D. Segransan
University of Geneva
A.E. Simon
University of Bern
Physics Institute
M. Stalport
University of Liège
S. Sulis
Laboratoire d'Astrophysique de Marseille
S. Udry
University of Geneva
S. Ulmer-Moll
University of Liège
University of Geneva
Physics Institute
J. Venturini
University of Geneva
E. Villaver
Instituto de Astrofísica de Canarias
V. Viotto
Istituto nazionale di astrofisica (INAF)
I. Walter
German Aerospace Center (DLR)
N. A. Walton
University of Cambridge
S. Wolf
University of Bern
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 693 A128Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
DOI
10.1051/0004-6361/202452151
Related datasets
WASP-33 CHEOPS light curves : J/A+A/693/A128 [dataset]
URI: https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/693/A128