| Title: |
TOI-544 b: a potential water-world inside the radius valley in a two-planet system |
| Authors: |
Osborne, HLM; Van Eylen, V; Goffo, E; Gandolfi, D; Nowak, G; Persson, CM; Livingston, J; Weeks, A; Palle, E; Luque, R; Hellier, C; Carleo, I; Redfield, S; Hirano, T; Garbaccio Gili, M; Alarcon, J; Barragan, O; Casasayas-Barris, N; Diaz, MR; Esposito, M; Knudstrup, E; Jenkins, JS; Murgas, F; Orell-Miquel, J; Rodler, F; Serrano, L; Stangret, M; Albrecht, SH; Alqasim, A; Cochran, WD; Deeg, HJ; Fridlund, M; Hatzes, AP; Korth, J; Lam, KWF |
| Source: |
Monthly Notices of the Royal Astronomical Society , 527 (4) pp. 11138-11157. (2024) |
| Publisher Information: |
OXFORD UNIV PRESS |
| Publication Year: |
2024 |
| Collection: |
University College London: UCL Discovery |
| Subject Terms: |
techniques: radial velocities; planets and satellites: composition; planets and satellites: detection |
| Description: |
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. |
| Document Type: |
article in journal/newspaper |
| File Description: |
application/pdf |
| Language: |
English |
| Relation: |
https://discovery.ucl.ac.uk/id/eprint/10187465/1/stad3837.pdf; https://discovery.ucl.ac.uk/id/eprint/10187465/ |
| Availability: |
https://discovery.ucl.ac.uk/id/eprint/10187465/1/stad3837.pdf; https://discovery.ucl.ac.uk/id/eprint/10187465/ |
| Rights: |
open |
| Accession Number: |
edsbas.191FECA3 |
| Database: |
BASE |