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

• Published in: arXiv.org 2022-09
• Main Authors: Grieves, Nolan, Bouchy, François, Ulmer-Moll, Solène, Gill, Samuel, Anderson, David R, Psaridi, Angelica, Lendl, Monika, Stassun, Keivan G, Jenkins, Jon M, Burleigh, Matthew R, Acton, Jack S, Boyd, Patricia T, Casewell, Sarah L, Eigmüller, Philipp, Goad, Michael R, Goeke, Robert F, Günther, Maximilian N, Hawthorn, Faith, Henderson, Beth A, Henze, Christopher E, Jordán, Andrés, Kendall, Alicia, Mishra, Lokesh, Moldovan, Dan, Moyano, Maximiliano, Osborn, Hugh, Revol, Alexandre, Sefako, Ramotholo R, Tilbrook, Rosanna H, Udry, Stéphane, Unger, Nicolas, Vines, Jose I, West, Richard G, Worters, Hannah L
• Format: Article
• Language: English
• Subjects: Circular orbits; Extrasolar planets; Gas giant planets; Iron; Jupiter; Metallicity; Planet detection; Planet formation; Planetary composition; Radial velocity; Saturn; Spectrographs; Transit
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2209.14830

We report the discovery of a 1.32\(^{+0.10}_{-0.10}\) \(\mathrm{M_{\rm Jup}}\) planet orbiting on a 75.12 day period around the G3V \(10.8^{+2.1}_{-3.6}\) 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\(^{+0.036}_{-0.035}\) \(\mathrm{R_{\rm Jup}}\) and an insolation of 9.6\(^{+0.9}_{-0.8}\) \(S_{\oplus}\), 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\(\pm\)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 \(\mathrm{M_{\rm Jup}}\) \(