A search for transiting planets around hot subdwarfs: I. Methods and performance tests on light curves from Kepler, K2, TESS, and CHEOPS
Journal article, 2021
Context. Hot subdwarfs experienced strong mass loss on the red giant branch (RGB) and are now hot and small He-burning objects. These stars constitute excellent opportunities for addressing the question of the evolution of exoplanetary systems directly after the RGB phase of evolution. Aims. In this project we aim to perform a transit survey in all available light curves of hot subdwarfs from space-based telescopes (Kepler, K2, TESS, and CHEOPS) with our custom-made pipeline SHERLOCK in order to determine the occurrence rate of planets around these stars as a function of orbital period and planetary radius. We also aim to determine whether planets that were previously engulfed in the envelope of their red giant host star can survive, even partially, as a planetary remnant. Methods. For this first paper, we performed injection-and-recovery tests of synthetic transits for a selection of representative Kepler, K2, and TESS light curves to determine which transiting bodies in terms of object radius and orbital period we will be able to detect with our tools. We also provide estimates for CHEOPS data, which we analyzed with the pycheops package. Results. Transiting objects with a radius ≤ 1.0 R⊕ can be detected in most of the Kepler, K2, and CHEOPS targets for the shortest orbital periods (1 d and shorter), reaching values as low as ∼0.3 R⊕ in the best cases. Sub-Earth-sized bodies are only reached for the brightest TESS targets and for those that were observed in a significant number of sectors. We also give a series of representative results for larger planets at greater distances, which strongly depend on the target magnitude and on the length and quality of the data. Conclusions. The TESS sample will provide the most important statistics for the global aim of measuring the planet occurrence rate around hot subdwarfs. The Kepler, K2, and CHEOPS data will allow us to search for planetary remnants, that is, very close and small (possibly disintegrating) objects.
Subdwarfs
Planetary systems
Techniques: photometric
Planet-star interactions
Stars: horizontal-branch
Author
V. Van Grootel
University of Liège
Francisco J. Pozuelos
University of Liège
A. Thuillier
University of Liège
S. Charpinet
University of Toulouse
L. Delrez
University of Liège
University of Geneva
M. Beck
University of Geneva
A. Fortier
University of Bern
S. Hoyer
Laboratoire d'Astrophysique de Marseille
S.G. Sousa
University of Porto
B. N. Barlow
High Point University
N. Billot
University of Geneva
M. Dévora-Pajares
Universidad de Granada
Valencian International University
R. H. Østensen
Missouri State University
Y. Alibert
University of Bern
R. Alonso
Instituto de Astrofísica de Canarias
University of La Laguna
G. Anglada Escude´
Institute of Space Sciences (ICE) - CSIC
Institute of Space Studies of Catalonia (IEEC)
J. Asquier
European Space Research and Technology Centre (ESA ESTEC)
D. Barrado
European Space Astronomy Centre (ESAC)
S.C.C. Barros
University of Porto
W. Baumjohann
Institut fur Weltraumforschung
T. Beck
University of Bern
A. Bekkelien
University of Geneva
W. Benz
University of Bern
X. Bonfils
Grenoble Alpes University
A. Brandeker
Stockholm University
C. Broeg
University of Bern
G. Bruno
Istituto nazionale di astrofisica (INAF)
T. Bárczy
Admatis
J. Cabrera
German Aerospace Center (DLR)
A.C. Cameron
University of St Andrews
S. Charnoz
Paris Descartes University
Melvyn B. Davies
Lund University
M. Deleuil
Laboratoire d'Astrophysique de Marseille
O. Demangeon
University of Porto
B.O. Demory
University of Bern
D. Ehrenreich
University of Geneva
Anders Erikson
German Aerospace Center (DLR)
L. Fossati
Institut fur Weltraumforschung
Malcolm Fridlund
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Leiden University
D. Futyan
University of Geneva
D. Gandolfi
University of Turin
Michaël Gillon
University of Liège
M. Guedel
University of Vienna
Kevin Heng
The University of Warwick
University of Bern
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L. Kiss
The University of Sydney
Eötvös Loránd University (ELTE)
Hungarian Academy of Sciences
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
Istituto nazionale di astrofisica (INAF)
P. Maxted
Keele University
M. Mecina
Institut fur Weltraumforschung
University of Vienna
A. J. Mustill
Lund University
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
G. Olofsson
Stockholm University
R. Ottensamer
University of Vienna
I. Pagano
Istituto nazionale di astrofisica (INAF)
E. Palle
Instituto de Astrofísica de Canarias
University of La Laguna
G. Peter
German Aerospace Center (DLR)
Giampaolo P. Piotto
University of Padua
Istituto nazionale di astrofisica (INAF)
J. Y. Plesseria
University of Liège
Don L. Pollacco
The University of Warwick
D. Queloz
University of Cambridge
University of Geneva
Roberto Ragazzoni
University of Padua
Istituto nazionale di astrofisica (INAF)
N. Rando
European Space Research and Technology Centre (ESA ESTEC)
H. Rauer
Technische Universität Berlin
Freie Universität Berlin
German Aerospace Center (DLR)
I. Ribas
Institute of Space Studies of Catalonia (IEEC)
Institute of Space Sciences (ICE) - CSIC
N. C. Santos
University of Porto
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
D. Segransan
University of Geneva
R. Silvotti
Istituto nazionale di astrofisica (INAF)
A.E. Simon
University of Bern
Alexis M. S. Smith
German Aerospace Center (DLR)
Manfred B. Steller
Institut fur Weltraumforschung
G.M. Szabó
Eötvös Loránd University (ELTE)
Nicolas Thomas
University of Bern
S. Udry
University of Geneva
V. Viotto
Istituto nazionale di astrofisica (INAF)
N. A. Walton
University of Cambridge
K. Westerdorff
German Aerospace Center (DLR)
T.G. Wilson
University of St Andrews
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 650 A205Subject Categories
Astronomy, Astrophysics and Cosmology
Biomedical Laboratory Science/Technology
Signal Processing
DOI
10.1051/0004-6361/202140381