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TOI-544 b:ã potential water-world inside the radius valley inã two-planet system

Osborne, H. L.M. ; Van Eylen, V. ; Goffo, E. ; Gandolfi, D. ; Nowak, G. ; Persson, C. M. ; Livingston, J. ; Weeks, A. ; Palle, E. and Luque, R. , et al. (2024) In Monthly Notices of the Royal Astronomical Society 527(4). p.11138-11157
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... (More)

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.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
planetsãnd satellites: composition, planetsãnd satellites: detection, techniques: radial velocities
in
Monthly Notices of the Royal Astronomical Society
volume
527
issue
4
pages
20 pages
publisher
Oxford University Press
external identifiers
  • scopus:85183445867
ISSN
0035-8711
DOI
10.1093/mnras/stad3837
language
English
LU publication?
yes
id
5af8cb63-ba01-4940-ba70-a3382503e353
date added to LUP
2024-02-19 15:37:42
date last changed
2024-02-19 15:37:57
@article{5af8cb63-ba01-4940-ba70-a3382503e353,
  abstract     = {{<p>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.</p>}},
  author       = {{Osborne, H. L.M. and Van Eylen, V. and Goffo, E. and Gandolfi, D. and Nowak, G. and Persson, C. M. and Livingston, J. and Weeks, A. and Palle, E. and Luque, R. and Hellier, C. and Carleo, I. and Redfield, S. and Hirano, T. and Gili, M. Garbaccio and Alarcon, J. and Barragan, O. and Casasayas-Barris, N. and Díaz, M. R. and Esposito, M. and Knudstrup, E. and Jenkins, J. S. and Murgas, F. and Orell-Miquel, J. and Rodler, F. and Serrano, L. and Stangret, M. and Albrecht, S. H. and Alqasim, A. and Cochran, W. D. and Deeg, H. J. and Fridlund, M. and Hatzes, A. P. and Korth, J. and Lam, K. W.F.}},
  issn         = {{0035-8711}},
  keywords     = {{planetsãnd satellites: composition; planetsãnd satellites: detection; techniques: radial velocities}},
  language     = {{eng}},
  month        = {{02}},
  number       = {{4}},
  pages        = {{11138--11157}},
  publisher    = {{Oxford University Press}},
  series       = {{Monthly Notices of the Royal Astronomical Society}},
  title        = {{TOI-544 b:ã potential water-world inside the radius valley inã two-planet system}},
  url          = {{http://dx.doi.org/10.1093/mnras/stad3837}},
  doi          = {{10.1093/mnras/stad3837}},
  volume       = {{527}},
  year         = {{2024}},
}