HR 10 as seen by CHEOPS and TESS: Revealing δ Scuti pulsations, granulation-like signal and hint for transients
Journal article, 2024
Context. HR 10 has only recently been identified as a binary system. Previously thought to be an A-type shell star, it appears that both components are fast-rotating A-type stars, each presenting a circumstellar envelope. Although showing complex photometric variability, spectroscopic observations of the metallic absorption lines reveal variation explained by the binarity, but not indicative of debris-disc inhomogeneities or sublimating exocomets. On the other hand, the properties of the two stars make them potential δ Scuti pulsators. Aims. The system has been observed in two sectors by the TESS satellite, and was the target of three observing visits by CHEOPS. Thanks to these new data, we aim to further characterise the stellar properties of the two components. In particular, we aim to decipher the extent to which the photometric variability can be attributed to a stellar origin. In complement, we searched in the lightcurves for transient-type events that could reveal debris discs or exocomets. Methods. We analysed the photometric variability of both the TESS and CHEOPS datasets in detail. We first performed a frequency analysis to identify and list all the periodic signals that may be related to stellar oscillations or surface variability. The signals identified as resulting from the stellar variability were then removed from the lightcurves in order to search for transient events in the residuals. Results. We report the detection of δ Scuti pulsations in both the TESS and CHEOPS data, but we cannot definitively identify which of the components is the pulsating star. In both datasets, we find flicker noise with the characteristics of a stellar granulation signal. However, it remains difficult to firmly attribute it to actual stellar granulation from convection, given the very thin surface convective zones predicted for both stars. Finally, we report probable detection of transient events in the CHEOPS data, without clear evidence of their origin.
Sun: granulation
Techniques: photometric
Stars: variables: δ Scuti
Circumstellar matter
Stars: fundamental parameters
Author
S. Salmon
University of Geneva
V. Van Grootel
University of Liège
S. Sulis
Laboratoire d'Astrophysique de Marseille
G.M. Szabó
Eötvös Loránd University (ELTE)
A. Brandeker
Stockholm University
C. Broeg
University of Bern
D. Ehrenreich
University of Geneva
S. Hoyer
Laboratoire d'Astrophysique de Marseille
S.G. Sousa
University of Porto
F. Kiefer
Paris Observatory
Institut d 'Astrophysique de Paris
D. Gandolfi
University of Turin
D. Nardiello
University of Padua
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
S. Charpinet
Institut de Recherche en Astrophysique et Planétologie (IRAP)
A. Bonfanti
Institut fur Weltraumforschung
T.G. Wilson
University of St Andrews
Y. Alibert
University of Bern
R. Alonso
Instituto de Astrofísica de Canarias
University of La Laguna
G. Anglada
Institute of Space Studies of Catalonia (IEEC)
Institute of Space Sciences (ICE) - CSIC
T. Bárczy
Admatis
D. Barrado Navascues
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
W. Benz
University of Bern
N. Billot
University of Geneva
X. Bonfils
Istituto nazionale di astrofisica (INAF)
L. Borsato
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
J. Cabrera
German Aerospace Center (DLR)
V. Cessa
University of Bern
S. Charnoz
Institut de Physique du Globe de Paris
A. Collier Cameron
University of St Andrews
C. Corral Van Damme
European Space Research and Technology Centre (ESA ESTEC)
Szilard Csizmadia
German Aerospace Center (DLR)
P. E. Cubillos
Istituto nazionale di astrofisica (INAF)
Institut fur Weltraumforschung
Melvyn B. Davies
Lund University
M. Deleuil
Laboratoire d'Astrophysique de Marseille
L. Delrez
University of Liège
O. Demangeon
University of Porto
B.O. Demory
University of Bern
Anders Erikson
German Aerospace Center (DLR)
A. Fortier
University of Bern
L. Fossati
Institut fur Weltraumforschung
Malcolm Fridlund
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Leiden University
Michaël Gillon
University of Liège
M. Gudel
University of Vienna
J. Hasiba
Institut fur Weltraumforschung
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L. L. Kiss
Hungarian Academy of Sciences
Eötvös Loránd University (ELTE)
J. Laskar
Paris Observatory
A. L. des Etangs
Institut d 'Astrophysique de Paris
M. Lendl
University of Geneva
C. Lovis
University of Geneva
D. Magrin
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
P. Maxted
Keele University
C. Mordasini
University of Bern
Valerio Nascimbeni
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
G. Olofsson
Stockholm University
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)
Giampaolo P. Piotto
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
University of Padua
Don L. Pollacco
The University of Warwick
D. Queloz
Swiss Federal Institute of Technology in Zürich (ETH)
University of Cambridge
Roberto Ragazzoni
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
University of Padua
N. Rando
European Space Research and Technology Centre (ESA ESTEC)
H. Rauer
Freie Universität Berlin
German Aerospace Center (DLR)
Technische 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
A. M.S. Smith
German Aerospace Center (DLR)
Manfred B. Steller
Institut fur Weltraumforschung
Nicolas Thomas
University of Bern
S. Udry
University of Geneva
J. Venturini
University of Geneva
V. Viotto
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
I. Walter
German Aerospace Center (DLR)
N. A. Walton
University of Cambridge
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 690 A73Subject Categories
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/202346180