The GAPS programme at TNG: XLIX. TOI-5398, the youngest compact multi-planet system composed of an inner sub-Neptune and an outer warm Saturn

0583668 - ASÚ 2025 RIV FR eng J - Journal Article
Mantovan, G. - Malavolta, L. - Desidera, S. - Kabáth, Petr … Total 71 authors
The GAPS programme at TNG: XLIX. TOI-5398, the youngest compact multi-planet system composed of an inner sub-Neptune and an outer warm Saturn.
Astronomy & Astrophysics. Roč. 682, February (2024), č. článku A129. ISSN 0004-6361. E-ISSN 1432-0746
R&D Projects: GA MŠMT(CZ) LTT20015
Institutional support: RVO:67985815
Keywords : planetary systems * planets and satellites * fundamental parameters
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 6.5, year: 2022
Method of publishing: Open access

We report the confirmation of TOI-5398, the youngest known compact multi-planet system composed of a hot sub-Neptune (TOI-5398 c, P-c = 4.77271 days) orbiting interior to a short-period Saturn (TOI-5398 b, P-b = 10.590547 days) planet, both transiting around a 650 +/- 150 Myr G-type star. As part of the Global Architecture of Planetary Systems (GAPS) Young Object project, we confirmed and characterised this compact system, measuring the radius and mass of both planets, thus constraining their bulk composition. Using multi-dimensional Gaussian processes, we simultaneously modelled stellar activity and planetary signals from the Transiting Exoplanet Survey Satellite (TESS) Sector 48 light curve and our High Accuracy Radial velocity Planet Searcher (HARPS-N) radial velocity (RV) time series. We confirmed the planetary nature of both planets, TOI-5398 b and TOI-5398 c, and obtained a precise estimation of their stellar parameters.
Permanent Link: https://hdl.handle.net/11104/0353353