Volume 645, January 2021
|Number of page(s)||19|
|Section||Planets and planetary systems|
|Published online||15 January 2021|
The GAPS Programme at TNG
XXVIII. A pair of hot-Neptunes orbiting the young star TOI-942★,★★
Astronomy Department and Van Vleck Observatory, Wesleyan University,
CT 06459, USA
2 INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
3 Aix Marseille Univ, CNRS, CNES, LAM, Marseille, France
4 Dipartimento di Fisica e Astronomia Galileo Galilei, Universitá di Padova, Vicolo dellOsservatorio 3, 35122 Padova, Italy
5 INAF – Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123 Catania, Italy
6 Department of Astronomy, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
7 INAF – Osservatorio Astronomico di Palermo, Piazza del Parlamento, 1, 90134 Palermo, Italy
8 Institute for Space Astrophysics and Planetology INAF-IAPS Via Fosso del Cavaliere 100, 00133 Roma, Italy
9 INAF – Osservatorio Astronomico di Brera, Via E. Bianchi 46, 23807 Merate, Italy
10 INAF – Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese, Italy
11 INAF – Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy
12 ETH Zürich, Institute for Particle Physics and Astrophysics, Wolfgang-Pauli-Str. 27, 8093 Zürich, Switzerland
13 INAF – Osservatorio Astronomico di Trieste, Via Tiepolo 11, 34143 Trieste, Italy
14 Fundación Galileo Galilei-INAF, Rambla José Ana Fernandez Pérez 7, 38712 Breña Baja, TF, Spain
15 INAF – Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, 80131 Napoli, Italy
16 Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenberg, Germany
17 Dipartimento di Fisica G. Occhialini, Università degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
18 Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
19 Department of Physics, University of Rome “Tor Vergata”, Via della Ricerca Scientifica 1, 00133 Rome, Italy
20 Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
21 INAF – Osservatorio Astronomico di Cagliari & REM, Via della Scienza, 5, 09047 Selargius CA, Italy
Accepted: 25 November 2020
Context. Young stars and multi-planet systems are two types of primary objects that allow us to study, understand, and constrain planetary formation and evolution theories.
Aims. We validate the physical nature of two Neptune-sized planets transiting TOI-942 (TYC 5909-319-1), a previously unacknowledged young star (50−20+30 Myr) observed by the TESS space mission in Sector 5.
Methods. Thanks to a comprehensive stellar characterization, TESS light curve modeling and precise radial-velocity measurements, we validated the planetary nature of the TESS candidate and detected an additional transiting planet in the system on a larger orbit.
Results. From photometric and spectroscopic observations we performed an exhaustive stellar characterization and derived the main stellar parameters. TOI-942 is a relatively active K2.5V star (log R′HK = −4.17 ± 0.01) with rotation period Prot = 3.39 ± 0.01 days, a projected rotation velocity v sin i⋆ = 13.8 ± 0.5 km s−1, and a radius of ~0.9 R⊙. We found that the inner planet, TOI-942 b, has an orbital period Pb = 4.3263 ± 0.0011 days, a radius Rb = 4.242−0.313+0.376 R⊕, and a mass upper limit of 16 M⊕ at 1σ confidence level. The outer planet, TOI-942 c, has an orbital period Pc = 10.1605−0.0053+0.0056 days, a radius Rc = 4.793−0.351+0.410 R⊕, and a mass upper limit of 37 M⊕ at 1σ confidence level.
Key words: planetary systems / techniques: photometric / techniques: spectroscopic / stars: fundamental parameters / techniques: radial velocities
Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated by the Fundación Galileo Galilei (FGG) of the Istituto Nazionale di Astrofisica (INAF) at the Observatorio del Roque de los Muchachos (La Palma, Canary Islands, Spain).
The authors became aware of a parallel effort on the characterization of TOI-942 by Zhou et al. (2021) in the late stages of the manuscript preparations. The submissions are coordinated, and no analyses or results were shared prior to submission.
© ESO 2021
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