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.

Techniques: photometric

Planet-star interactions

Planetary systems

Stars: horizontal-branch

Subdwarfs

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

University of La Laguna

Instituto Astrofisico de Canarias

G. Anglada Escude´

Institute of Space Studies of Catalonia (IEEC)

Institute of Space Sciences (ICE) - CSIC

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

Osservatorio Astrofisico di Catania

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

University of Bern

The University of Warwick

K. Isaak

European Space Research and Technology Centre (ESA ESTEC)

L. Kiss

Eötvös Loránd University (ELTE)

Hungarian Academy of Sciences

The University of Sydney

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

Osservatorio Astronomico di Padova

P. Maxted

Keele University

M. Mecina

University of Vienna

Institut fur Weltraumforschung

A. J. Mustill

Lund University

Valerio Nascimbeni

Osservatorio Astronomico di Padova

G. Olofsson

Stockholm University

R. Ottensamer

University of Vienna

I. Pagano

Osservatorio Astrofisico di Catania

E. Palle

University of La Laguna

Instituto Astrofisico de Canarias

G. Peter

German Aerospace Center (DLR)

Giampaolo P. Piotto

Osservatorio Astronomico di Padova

University of Padua

J. Y. Plesseria

University of Liège

Don L. Pollacco

The University of Warwick

D. Queloz

University of Geneva

University of Cambridge

Roberto Ragazzoni

Osservatorio Astronomico di Padova

University of Padua

N. Rando

European Space Research and Technology Centre (ESA ESTEC)

H. Rauer

German Aerospace Center (DLR)

Freie Universität Berlin

Technische Universität Berlin

I. Ribas

Institute of Space Studies of Catalonia (IEEC)

Institute of Space Sciences (ICE) - CSIC

N. C. Santos

University of Porto

Gaetano Scandariato

Osservatorio Astrofisico di Catania

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

Osservatorio Astronomico di Padova

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 A205

Subject Categories

Astronomy, Astrophysics and Cosmology

Biomedical Laboratory Science/Technology

Signal Processing

DOI

10.1051/0004-6361/202140381

More information

Latest update

7/8/2021 2