Issue |
A&A
Volume 690, October 2024
|
|
---|---|---|
Article Number | A349 | |
Number of page(s) | 16 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202450852 | |
Published online | 22 October 2024 |
The K2-24 planetary system revisited by CHEOPS
1
INAF, Osservatorio Astronomico di Padova,
Vicolo dell’Osservatorio 5,
35122
Padova,
Italy
2
Dipartimento di Fisica e Astronomia, Università degli Studi di Padova,
Vicolo dell’Osservatorio 3,
35122
Padova,
Italy
3
Instituto de Astrofisica e Ciencias do Espaco, Universidade do Porto, CAUP,
Rua das Estrelas,
4150-762
Porto,
Portugal
4
Department of Physics, University of Warwick,
Gibbet Hill Road,
Coventry
CV4 7AL,
UK
5
Weltraumforschung und Planetologie, Physikalisches Institut, University of Bern,
Gesellschaftsstrasse 6,
3012
Bern,
Switzerland
6
Center for Space and Habitability, University of Bern,
Gesellschaftsstrasse 6,
3012
Bern,
Switzerland
7
Observatoire astronomique de l’Université de Genève,
Chemin Pegasi 51,
1290
Versoix,
Switzerland
8
Department of Astronomy & Astrophysics, University of Chicago,
Chicago,
IL
60637,
USA
9
Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università degli Studi di Padova,
Vicolo dell’Osservatorio 3,
35122
Padova,
Italy
10
Instituto de Astrofísica de Canarias,
Vía Láctea s/n,
38200
La Laguna, Tenerife,
Spain
11
Departamento de Astrofísica, Universidad de La Laguna,
Astrofísico Francisco Sanchez s/n,
38206
La Laguna, Tenerife,
Spain
12
Admatis,
5, Kandó Kálmán Street,
3534
Miskolc,
Hungary
13
Depto. de Astrofísica, Centro de Astrobiología (CSIC-INTA),
ESAC campus,
28692
Villanueva de la Cañada (Madrid),
Spain
14
Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto,
Rua do Campo Alegre,
4169-007
Porto,
Portugal
15
Space Research Institute, Austrian Academy of Sciences,
Schmiedl-strasse 6,
8042
Graz,
Austria
16
Max Planck Institute for Extraterrestrial Physics,
Gießenbachstraße,
85748
Garching,
Germany
17
Department of Astronomy, Stockholm University, AlbaNova University Center,
10691
Stockholm,
Sweden
18
Physikalisches Institut, University of Bern,
Gesellschaftsstrasse 6,
3012
Bern,
Switzerland
19
Centre for Exoplanet Science, SUPA School of Physics and Astronomy, University of St Andrews,
North Haugh,
St Andrews
KY16 9SS,
UK
20
CFisUC, Departamento de Física, Universidade de Coimbra,
3004516
Coimbra,
Portugal
21
Institute of Planetary Research, German Aerospace Center (DLR),
Rutherfordstrasse 2,
12489
Berlin,
Germany
22
INAF, Osservatorio Astrofisico di Torino,
Via Osservatorio, 20,
10025
Pino Torinese To,
Italy
23
Centre for Mathematical Sciences, Lund University,
Box 118,
221 00
Lund,
Sweden
24
Aix Marseille Univ., CNRS, CNES, LAM,
38 rue Frédéric Joliot-Curie,
13388
Marseille,
France
25
Astrobiology Research Unit, Université de Liège,
Allée du 6 Août 19C,
4000
Liège,
Belgium
26
Space sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège,
Allée du 6 Août 19C,
4000
Liège,
Belgium
27
Institute of Astronomy, KU Leuven,
Celestijnenlaan 200D,
3001
Leuven,
Belgium
28
ELTE Gothard Astrophysical Observatory,
9700
Szombathely,
Szent Imre h. u. 112,
Hungary
29
SRON Netherlands Institute for Space Research,
Niels Bohrweg 4,
2333
CA
Leiden,
The Netherlands
30
Centre Vie dans l’Univers, Faculté des sciences, Université de Genève,
Quai Ernest-Ansermet 30,
1211
Genève 4,
Switzerland
31
Leiden Observatory, University of Leiden,
PO Box 9513,
2300 RA
Leiden,
The Netherlands
32
Department of Space, Earth and Environment, Chalmers University of Technology,
Onsala Space Observatory,
439 92
Onsala,
Sweden
33
Dipartimento di Fisica, Università degli Studi di Torino,
via Pietro Giuria 1,
10125
Torino,
Italy
34
National and Kapodistrian University of Athens, Department of Physics,
University Campus, Zografos 157 84,
Athens,
Greece
35
Department of Astrophysics, University of Vienna,
Türkenschanzs-trasse 17,
1180
Vienna,
Austria
36
European Space Agency (ESA), European Space Research and Technology Centre (ESTEC),
Keplerlaan 1,
2201 AZ
Noordwijk,
The Netherlands
37
Institute for Theoretical Physics and Computational Physics, Graz University of Technology,
Petersgasse 16,
8010
Graz,
Austria
38
Konkoly Observatory, Research Centre for Astronomy and Earth Sciences,
1121
Budapest,
Konkoly Thege Miklós út 15-17,
Hungary
39
ELTE Eötvös Loránd University, Institute of Physics,
Pázmány Péter sétány 1/A,
1117
Budapest,
Hungary
40
Lund Observatory, Division of Astrophysics, Department of Physics, Lund University,
Box 118,
22100
Lund,
Sweden
41
IMCCE, UMR8028 CNRS, Observatoire de Paris, PSL Univ., Sorbonne Univ.,
77 av. Denfert-Rochereau,
75014
Paris,
France
42
Institut d’astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie,
98bis blvd. Arago,
75014
Paris,
France
43
Astrophysics Group, Lennard Jones Building, Keele University,
Staffordshire
ST5 5BG,
UK
44
European Space Agency, ESA – European Space Astronomy Centre,
Camino Bajo del Castillo s/n,
28692
Villanueva de la Cañada, Madrid,
Spain
45
INAF, Osservatorio Astrofisico di Catania,
Via S. Sofia 78,
95123
Catania,
Italy
46
Institute of Optical Sensor Systems, German Aerospace Center (DLR),
Rutherfordstrasse 2,
12489
Berlin,
Germany
47
ETH Zurich, Department of Physics,
Wolfgang-Pauli-Strasse 2,
CH-8093
Zurich,
Switzerland
48
Cavendish Laboratory,
JJ Thomson Avenue,
Cambridge
CB3 0HE,
UK
49
Institut fuer Geologische Wissenschaften, Freie Universitaet Berlin,
Maltheserstrasse 74-100,
12249
Berlin,
Germany
50
Institut de Ciencies de l’Espai (ICE, CSIC),
Campus UAB, Can Magrans s/n,
08193
Bellaterra,
Spain
51
Institut d’Estudis Espacials de Catalunya (IEEC),
08860
Castellde-fels (Barcelona),
Spain
52
ESOC, European Space Agency,
Robert-Bosch-Str. 5,
64293
Darmstadt,
Germany
53
HUN-REN-ELTE Exoplanet Research Group,
Szent Imre h. u. 112.,
Szombathely
9700,
Hungary
54
Institute of Astronomy, University of Cambridge,
Madingley Road,
Cambridge
CB3 0HA,
UK
55
Dipartimento di Fisica, Università di Trento,
Via Sommarive 14,
38123
Povo (TN),
Italy
★ Corresponding author; valerio.nascimbeni@inaf.it
Received:
23
May
2024
Accepted:
4
September
2024
The planetary system K2-24 is composed of two transiting low-density Neptunians locked in an almost perfect 2:1 resonance and showing large transit time variations (TTVs), and it is an excellent laboratory to search for signatures of planetary migration. Previous studies performed with K2, Spitzer, and RV data tentatively claimed a significant non-zero eccentricity for one or both planets, possibly high enough to challenge the scenario of pure disk migration through resonant capture. With 13 new CHEOPS light curves (seven of planet b, six of planet c), we carried out a global photometric and dynamical re-analysis by including all the available literature data as well. We obtained the most accurate set of planetary parameters to date for the K2-24 system, including radii and masses at 1% and 5% precision (now essentially limited by the uncertainty on stellar parameters) and non-zero eccentricities eb = 0.0498−0.0018+0.0011, ec = 0.0282−0.0007+0.0003 detected at very high significance for both planets. Such relatively large values imply the need for an additional physical mechanism of eccentricity excitation during or after the migration stage. Also, while the accuracy of the previous TTV model had drifted by up to 0.5 days at the current time, we constrained the orbital solution firmly enough to predict the forthcoming transits for the next ~15 years, thus enabling efficient follow-up with top-level facilities such as JWST or ESPRESSO.
Key words: techniques: photometric / techniques: spectroscopic / planets and satellites: detection / planets and satellites: dynamical evolution and stability / planets and satellites: gaseous planets
© The Authors 2024
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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