학술논문
TOI-544 b:ã potential water-world inside the radius valley inã two-planet system
Document Type
Author
Osborne, H. L.M.; Van Eylen, V.; Goffo, E.; Gandolfi, D.; Nowak, G.; Persson, C. M.; Livingston, J.; Weeks, A.; Palle, E.; Luque, R.; Hellier, C.; Carleo, I.; Redfield, S.; Hirano, T.; Gili, M. Garbaccio; Alarcon, J.; Barragan, O.; Casasayas-Barris, N.; Díaz, M. R.; Esposito, M.; Knudstrup, E.; Jenkins, J. S.; Murgas, F.; Orell-Miquel, J.; Rodler, F.; Serrano, L.; Stangret, M.; Albrecht, S. H.; Alqasim, A.; Cochran, W. D.; Deeg, H. J.; Fridlund, M.; Hatzes, A. P.; Korth, J.; Lam, K. W.F.
Source
Monthly Notices of the Royal Astronomical Society. 527(4):11138-11157
Subject
Language
English
ISSN
0035-8711
Abstract
We report on the precise radial velocity follow-up of TOI-544 (HD 290498),ã bright K star ( V = 10.8), which hostsã small transiting planet recently disco v ered by the Trãnsiting Exoplanet Survey Satellite (TESS) . We collected 122 high-resolution High Accuracy Radial velocity Planet Searcher (HARPS)ãnd HARPS-N spectra to spectroscopically confirm the transiting planetãnd measure its mass. The nearly 3-yr baseline of our follow-upãllowed us to unveil the presence ofãnãdditional, non-transiting, longer-period companion planet. We derivedã radiusãnd mass for the inner planet, TOI-544 b, of 2.018 ±0.076 R⊙and 2.89 ±0.48 M⊙, respectively, which givesã bulk density of 1 . 93 + 0 . 30 -0 . 25 g cm -3 . TOI-544 c hasã minimum mass of 21.5 ±2.0 M⊙and orbital period of 50.1 ±0.2 d. The low density of planet-b implies that it has eitherãn Earth-like rocky core withã hydrogenãtmosphere, orã composition which harboursã significant fraction of water. The composition interpretation is degenerate depending on the specific choice of planet interior models used. Additionally, TOI-544 b hasãn orbital period of 1.55 dãnd equilibrium temperature of 999 ±14 K, placing it within the predicted location of the radius valley, where few planetsãre expected. TOI-544 b isã top target for futureãtmospheric observations, for example with JWST , which would enable better constraints of the planet composition.