An old warm Jupiter orbiting the metal-poor G-dwarf TOI-5542

Nolan Grieves, François Bouchy, Solène Ulmer-Moll, Samuel Gill, David R. Anderson, Angelica Psaridi, Monika Lendl, Keivan G. Stassun, Jon M. Jenkins, Matthew R. Burleigh, Jack S. Acton, Patricia T. Boyd, Sarah L. Casewell, Philipp Eigmüller, Michael R. Goad, Robert F. Goeke, Maximilian N. Günther, Faith Hawthorn, Beth A. Henderson, Christopher E. HenzeAndrés Jordán, Alicia Kendall, Lokesh Mishra, Maximiliano Moyano, Hugh Osborn, Alexandre Revol, Ramotholo R. Sefako, Rosanna H. Tilbrook, Stéphane Udry, Nicolas Unger, Jose I. Vines, Richard G. West, Hannah L. Worters

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


We report the discovery of a 1.32-0.10+0.10 MJup planet orbiting on a 75.12 day period around the G3V 10.8-3.6+2.1 Gyr old star TOI-5542 (TIC 466206508; TYC 9086-1210-1). The planet was first detected by the Transiting Exoplanet Survey Satellite (TESS) as a single transit event in TESS Sector 13. A second transit was observed 376 days later in TESS Sector 27. The planetary nature of the object has been confirmed by ground-based spectroscopic and radial velocity observations from the CORALIE and HARPS spectrographs. A third transit event was detected by the ground-based facilities NGTS, EulerCam, and SAAO. We find the planet has a radius of 1.009-0.035+0.036 RJup and an insolation of 9.6-0.8+0.9 S⊕, along with a circular orbit that most likely formed via disk migration or in situ formation, rather than high-eccentricity migration mechanisms. Our analysis of the HARPS spectra yields a host star metallicity of [Fe/H] = -0.21 ± 0.08, which does not follow the traditional trend of high host star metallicity for giant planets and does not bolster studies suggesting a difference among low- and high-mass giant planet host star metallicities. Additionally, when analyzing a sample of 216 well-characterized giant planets, we find that both high masses (4 MJup < Mp < 13 MJup) and low masses (0.5 MJup < Mp < 4 MJup), as well as both both warm (P > 10 days) and hot (P < 10 days) giant planets are preferentially located around metal-rich stars (mean [Fe/H] > 0.1). TOI-5542b is one of the oldest known warm Jupiters and it is cool enough to be unaffected by inflation due to stellar incident flux, making it a valuable contribution in the context of planetary composition and formation studies.

Original languageEnglish
Article numberA29
JournalAstronomy and Astrophysics
StatePublished - 1 Dec 2022
Externally publishedYes


  • Planets and satellites: detection
  • Planets and satellites: dynamical evolution and stability
  • Planets and satellites: formation
  • Planets and satellites: fundamental parameters
  • Planets and satellites: gaseous planets


Dive into the research topics of 'An old warm Jupiter orbiting the metal-poor G-dwarf TOI-5542'. Together they form a unique fingerprint.

Cite this