Characterization of the HD 108236 system with CHEOPS and TESS Confirmation of a fifth transiting planet
Journal article, 2022
Context. The HD 108236 system was first announced with the detection of four small planets based on TESS data. Shortly after, the transit of an additional planet with a period of 29.54 d was serendipitously detected by CHEOPS. In this way, HD 108236 (V = 9.2) became one of the brightest stars known to host five small transiting planets (Rp < 3 Ro˙). Aims. We characterize the planetary system by using all the data available from CHEOPS and TESS space missions. We use the flexible pointing capabilities of CHEOPS to follow up the transits of all the planets in the system, including the fifth transiting body. Methods. After updating the host star parameters by using the results from Gaia eDR3, we analyzed 16 and 43 transits observed by CHEOPS and TESS, respectively, to derive the planets' physical and orbital parameters. We carried out a timing analysis of the transits of each of the planets of HD 108236 to search for the presence of transit timing variations. Results. We derived improved values for the radius and mass of the host star (R∗ = 0.876 ± 0.007 R0 and M∗ = 0.867-0.046+0.047M). We confirm the presence of the fifth transiting planet f in a 29.54 d orbit. Thus, the HD 108236 system consists of five planets of Rb = 1.587±0.028, Rc = 2.122±0.025, Rd = 2.629 ± 0.031, Re = 3.008 ± 0.032, and Rf = 1.89 ± 0.04 [Ro˙]. We refine the transit ephemeris for each planet and find no significant transit timing variations for planets c, d, and e. For planets b and f, instead, we measure significant deviations on their transit times (up to 22 and 28 min, respectively) with a non-negligible dispersion of 9.6 and 12.6 min in their time residuals. Conclusions. We confirm the presence of planet f and find no significant evidence for a potential transiting planet in a 10.9 d orbital period, as previously suggested. Further monitoring of the transits, particularly for planets b and f, would confirm the presence of the observed transit time variations. HD 108236 thus becomes a key multi-planetary system for the study of formation and evolution processes. The reported precise results on the planetary radii - together with a profuse RV monitoring - will allow for an accurate characterization of the internal structure of these planets.
Planets and satellites: detection
Planets and satellites: individual: HD 108236
Planets and satellites: individual: TOI 1233
Planetary systems
Planets and satellites: fundamental parameters
Author
S. Hoyer
Laboratoire d'Astrophysique de Marseille
A. Bonfanti
Institut fur Weltraumforschung
A. Leleu
University of Geneva
University of Bern
L. Acuña
Laboratoire d'Astrophysique de Marseille
L. M. Serrano
University of Turin
M. Deleuil
Laboratoire d'Astrophysique de Marseille
A. Bekkelien
University of Geneva
C. Broeg
University of Bern
H.-G. Florén
Stockholm University
D. Queloz
University of Cambridge
Swiss Federal Institute of Technology in Zürich (ETH)
T.G. Wilson
University of St Andrews
S.G. Sousa
University of Porto
M.J. Hooton
University of Cambridge
University of Bern
V. Adibekyan
University of Porto
Y. Alibert
University of Bern
R. Alonso
University of La Laguna
Instituto de Astrofísica de Canarias
G. Anglada
Institute of Space Studies of Catalonia (IEEC)
Institute of Space Sciences (ICE) - CSIC
J. Asquier
European Space Research and Technology Centre (ESA ESTEC)
T. Bárczy
Admatis
D. Barrado
European Space Astronomy Centre (ESAC)
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
F. Biondi
Istituto nazionale di astrofisica (INAF)
Max Planck Society
X. Bonfils
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
A. Brandeker
Stockholm University
J. Cabrera
German Aerospace Center (DLR)
S. Charnoz
Institut de Physique du Globe de Paris
A. Collier Cameron
University of St Andrews
Szilard Csizmadia
German Aerospace Center (DLR)
M. B. Davies
Lund University
L. Delrez
University of Liège
O. Demangeon
University of Porto
B.O. Demory
University of Bern
D. Ehrenreich
University of Geneva
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
D. Gandolfi
University of Turin
Michaël Gillon
University of Liège
M. Gudel
University of Vienna
N.C. Hara
University of Geneva
Kevin Heng
The University of Warwick
University of Bern
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
Jon M. Jenkins
NASA Ames Research Center
L. Kiss
Hungarian Academy of Sciences
Eötvös Loránd University (ELTE)
J. Laskar
Paris Observatory
D. W. Latham
Harvard-Smithsonian Center for Astrophysics
A. L. des Etangs
Institut d 'Astrophysique de Paris
M. Lendl
University of Geneva
C. Lovis
University of Geneva
A. Luntzer
University of Vienna
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. Maxted
Keele University
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
G. Olofsson
Stockholm University
R. Ottensamer
University of Vienna
I. Pagano
Istituto nazionale di astrofisica (INAF)
Enric Palle
Instituto de Astrofísica de Canarias
Carina Persson
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
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
The University of Warwick
Roberto Ragazzoni
Istituto nazionale di astrofisica (INAF)
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 Studies of Catalonia (IEEC)
Institute of Space Sciences (ICE) - CSIC
George R. Ricker
Massachusetts Institute of Technology (MIT)
S. Salmon
University of Geneva
N. C. Santos
University of Porto
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
S. Seager
Massachusetts Institute of Technology (MIT)
D. Segransan
University of Geneva
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
J. D. Twicken
NASA Ames Research Center
SETI Institute
S. Udry
University of Geneva
V. Van Grootel
University of Liège
Roland K. Vanderspek
Massachusetts Institute of Technology (MIT)
N. A. Walton
University of Cambridge
K. Westerdorff
German Aerospace Center (DLR)
J. N. Winn
Princeton University
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 668 A117Exoplanets from space -CHEOPS and PLATO ESA's next two projects (Phase 2)
Swedish National Space Board (177/19), 2020-01-01 -- 2022-12-31.
Swedish National Space Board (65/19), 2020-01-01 -- 2022-12-31.
Subject Categories
Astronomy, Astrophysics and Cosmology
Other Physics Topics
Theoretical Chemistry
DOI
10.1051/0004-6361/202243720