Issue |
A&A
Volume 668, December 2022
|
|
---|---|---|
Article Number | A117 | |
Number of page(s) | 25 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202243720 | |
Published online | 13 December 2022 |
Characterization of the HD 108236 system with CHEOPS and TESS Confirmation of a fifth transiting planet★
1
Aix-Marseille Univ., CNRS, CNES, LAM,
38 rue Frédéric Joliot-Curie,
13388
Marseille, France
e-mail: sergio.hoyer@lam.fr
2
Space Research Institute, Austrian Academy of Sciences,
Schmiedlstrasse 6,
8042
Graz, Austria
3
Observatoire Astronomique de l’Université de Genève,
Chemin Pegasi 51,
Versoix, Switzerland
4
Physikalisches Institut, University of Bern,
Gesellsschaftstrasse 6,
3012
Bern, Switzerland
5
Dipartimento di Fisica, Universita degli Studi di Torino,
via Pietro Giuria 1,
10125
Torino, Italy
6
Center for Space and Habitability,
Gesellsschaftstrasse 6,
3012
Bern, Switzerland
7
Department of Astronomy, Stockholm University, AlbaNova University Center,
10691
Stockholm, Sweden
8
Department of Astronomy, Stockholm University,
106 91
Stockholm, Sweden
9
ETH Zurich, Department of Physics,
Wolfgang-Pauli-Strasse 2,
8093
Zurich, Switzerland
10
Cavendish Laboratory,
JJ Thomson Avenue,
Cambridge
CB3 0HE, UK
11
Centre for Exoplanet Science, SUPA School of Physics and Astronomy, University of St Andrews,
North Haugh,
St Andrews
KY16 9SS, UK
12
Instituto de Astrofisica e Ciencias do Espaco, Universidade do Porto, CAUP,
Rua das Estrelas,
4150-762
Porto, Portugal
13
Instituto de Astrofisica de Canarias,
38200
La Laguna, Tenerife, Spain
14
Departamento de Astrofisica, Universidad de La Laguna,
38206
La Laguna, Tenerife, Spain
15
Institut de Ciencies de l’Espai (ICE, CSIC),
Campus UAB, Can Magrans s/n,
08193
Bellaterra, Spain
16
Institut d’Estudis Espacials de Catalunya (IEEC),
08034
Barcelona, Spain
17
ESTEC, European Space Agency,
2201AZ
Noordwijk, NL, The Netherlands
18
Admatis,
5. Kandó Kálmán Street,
3534
Miskolc, Hungary
19
Depto. de Astrofisica, Centro de Astrobiologia (CSIC-INTA),
ESAC campus,
28692
Villanueva de la Cañada (Madrid), Spain
20
Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto,
Rua do Campo Alegre,
4169-007
Porto, Portugal
21
Max Planck Institute for Extraterrestrial Physics,
Gießenbachstraße 1,
85748
Garching bei München, Germany
22
INAF, Osservatorio Astronomico di Padova,
Vicolo dell’Osservatorio 5,
35122
Padova, Italy
23
Université Grenoble Alpes, CNRS, IPAG,
38000
Grenoble, France
24
Institute of Planetary Research, German Aerospace Center (DLR),
Rutherfordstrasse 2,
12489
Berlin, Germany
25
Université de Paris, Institut de physique du globe de Paris, CNRS,
75005
Paris, France
26
Centre for Mathematical Sciences, Lund University,
Box 118,
221 00
Lund, Sweden
27
Astrobiology Research Unit, Université de Liège,
Allée du 6 Août 19C,
4000
Liège, Belgium
28
Space sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège,
Allée du 6 Août 19C,
4000
Liège, Belgium
29
Leiden Observatory, University of Leiden,
PO Box 9513,
2300 RA
Leiden, The Netherlands
30
Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory,
43992
Onsala, Sweden
31
University of Vienna, Department of Astrophysics,
Türkenschanzstrasse 17,
1180
Vienna, Austria
32
Department of Physics, University of Warwick,
Gibbet Hill Road,
Coventry
CV4 7AL, UK
33
Science and Operations Department – Science Division (SCI-SC), Directorate of Science, European Space Agency (ESA), European Space Research and Technology Centre (ESTEC),
Keplerlaan 1,
2201-AZ
Noordwijk, The Netherlands
34
NASA Ames Research Center,
Moffett Field, CA,
94035, USA
35
Konkoly Observatory, Research Centre for Astronomy and Earth Sciences,
1121
Budapest,
Konkoly Thege Miklós út 15-17, Hungary
36
ELTE Eötvös Loránd University, Institute of Physics,
Pázmány Péter sétány 1/A,
Budapest
1117, Hungary
37
IMCCE, UMR8028 CNRS, Observatoire de Paris, PSL Univ.,
Sorbonne Univ., 77 av. Denfert-Rochereau,
75014
Paris, France
38
Center for Astrophysics, Harvard & Smithsonian,
60 Garden Street,
Cambridge, MA,
02138, USA
39
Institut d’astrophysique de Paris, CNRS, UMR 7095, Sorbonne Université,
98 bis bd Arago,
75014
Paris, France
40
Department of Astrophysics, University of Vienna,
Tuerkenschanzstrasse 17,
1180
Vienna, Austria
41
Astrophysics Group, Keele University,
Staffordshire,
ST5 5BG, UK
42
INAF, Osservatorio Astrofisico di Catania,
Via S. Sofia 78,
95123
Catania, Italy
43
Institute of Optical Sensor Systems, German Aerospace Center (DLR),
Rutherfordstrasse 2,
12489
Berlin, Germany
44
Dipartimento di Fisica e Astronomia “Galileo Galilei”, Universita degli Studi di Padova,
Vicolo dell’Osservatorio 3,
35122
Padova, Italy
45
Zentrum für Astronomie und Astrophysik, Technische Universität Berlin,
Hardenbergstr. 36,
10623
Berlin, Germany
46
Institut für Geologische Wissenschaften, Freie Universität Berlin,
12249
Berlin, Germany
47
Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology,
Cambridge, MA,
02139, USA
48
Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology,
Cambridge, MA,
02139, USA
49
Department of Aeronautics and Astronautics, MIT,
77 Massachusetts Avenue,
Cambridge, MA,
02139, USA
50
ELTE Eötvös Loránd University, Gothard Astrophysical Observatory,
9700
Szombathely,
Szent Imre h. u. 112, Hungary
51
MTA-ELTE Exoplanet Research Group,
9700
Szombathely,
Szent Imre h. u. 112, Hungary
52
SETI Institute,
Mountain View, CA
94043, USA
53
Institute of Astronomy, University of Cambridge,
Madingley Road,
Cambridge,
CB3 0HA, UK
54
Department of Astrophysical Sciences, Princeton University,
4 Ivy Ln.,
Princeton NJ
08544, USA
Received:
5
April
2022
Accepted:
4
September
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 R⊕).
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 [R⊕]. 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.
Key words: planetary systems / planets and satellites: detection / planets and satellites: fundamental parameters / planets and satellites: individual: HD 108236 / planets and satellites: individual: TOI 1233
CHEOPS detrended light curves are only available in electronic format the CDS via anonymous ftp to cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/668/A117
© S. Hoyer et al. 2022
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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