Issue |
A&A
Volume 688, August 2024
|
|
---|---|---|
Article Number | A15 | |
Number of page(s) | 24 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202450679 | |
Published online | 30 July 2024 |
TOI-837 b: Characterisation, formation, and evolutionary history of an infant warm Saturn-mass planet
1
INAF – Osservatorio Astrofisico di Torino,
Via Osservatorio 20,
10025
Pino Torinese,
Italy
e-mail: mario.damasso@inaf.it
2
INAF – Osservatorio Astronomico di Trieste,
Via Giambattista Tiepolo, 11,
34131
Trieste (TS),
Italy
3
INAF – Osservatorio Astronomico di Palermo,
Piazza del Parlamento 1,
90134
Palermo,
Italy
4
Space Research Institute, Austrian Academy of Sciences,
Schmiedlstrasse 6,
8042
Graz,
Austria
5
ESO-European Southern Observatory,
Alonso de Cordova 3107, Vitacura,
Santiago,
Chile
6
INAF – Osservatorio Astronomico di Roma,
Via Frascati 33,
00078
Monte Porzio Catone (Roma),
Italy
7
Dipartimento di Fisica e Astronomia “G. Galilei”– Università degli Studi di Padova,
Vicolo dell’Osservatorio 3,
35122
Padova,
Italy
8
INAF – Osservatorio Astronomico di Padova,
Vicolo dell’Osservatorio 5,
35122
Padova,
Italy
Received:
10
May
2024
Accepted:
12
June
2024
Context. The detection and characterisation of planets younger than ~100 Myr offer the opportunity to get snapshots of systems immediately after their formation, where the main evolutionary processes that sculpt mature planetary systems are still ongoing. Known infant exoplanets are currently scarce, and dedicated surveys are required to increase their number.
Aims. We aim to determine the fundamental properties of the ~35 Myr old star TOI-837 and its close-in Saturn-sized planet, and to investigate the system’s formation and evolutionary history.
Methods. We analysed TESS photometry and HARPS spectroscopic data, measured stellar and planetary parameters, and characterised the stellar activity. We performed population synthesis simulations to track the formation history of TOI-837 b, and to reconstruct its possible internal structure. We investigated the planetary atmospheric evolution through photo-evaporation, and quantified the prospects for atmospheric characterisation with JWST.
Results. TOI-837 b has similar radius, mass, and bulk density to those of Saturn (rb=9.71−0.60+0.93 R⊕, mb=116−18+17 M⊕, and ρb=0.68−0.18+0.20 g cm−3) and is on a primordial circular orbit. Population synthesis and early migration simulations suggest that the planet could have originally formed between 2 and 4 au, and have either a large and massive core, or a smaller Saturn-like core, depending on the opacity of the protoplanetary gas and on the growth rate of the core. We find that photo-evaporation produced negligible effects even at early ages (3–10 Myr). Transmission spectroscopy with JWST is very promising, and is expected to provide constraints on atmospheric metallicity and the abundances of H2O, CO2, and CH4 molecules, and to probe the presence of refractory elements.
Conclusions. TOI-837 offers valuable prospects for follow-up observations, which are needed for a thorough characterisation. JWST will help to better constrain the formation and evolution history of the system, and to clarify whether or not TOI-837 b is a Saturn-analogue.
Key words: techniques: photometric / techniques: radial velocities / planets and satellites: composition / planets and satellites: detection / stars: individual: TOI-837
© 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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