The mass of TOI-519 b: A close-in giant planet transiting a metal-rich mid-M dwarf
Taiki Kagetani, Norio Narita, Tadahiro Kimura, Teruyuki Hirano, Masahiro Ikoma, Hiroyuki Ishikawa, Steven Giacalone, Akihiko Fukui, Takanori Kodama, Rebecca Gore, Ashley Schroeder, Yasunori Hori, Kiyoe Kawauchi, Noriharu Watanabe, M. Mori, Yujie Zou, Kai Ikuta, Vigneshwaran Krishnamurthy, Jon K. Zink, Kevin K. Hardegree-Ullman, Hiroki Harakawa, Tomoyuki Kudo, Takayuki Kotani, Takashi Kurokawa, Nobuhiko Kusakabe, Masayuki Kuzuhara, Jerome de Leon, John H. Livingston, Jun Nishikawa, Masashi Omiya, Ε. Πάλλη, H. Parviainen, Takuma Serizawa, Huan-Yu Teng, Akitoshi Ueda, Motohide Tamura
Abstract
Abstract We report on the determination of the mass of TOI-519 b, a transiting substellar object around a mid-M dwarf. We carried out radial velocity measurements using Subaru/InfraRed Doppler (IRD), revealing that TOI-519 b is a planet with a mass of $0.463^{+0.082}_{-0.088}\, M_{\rm Jup}$. We also found that the host star is metal rich ([Fe/H] = 0.27 ± 0.09 dex) and has the lowest effective temperature (Teff = 3322 ± 49 K) among all stars hosting known close-in giant planets based on the IRD spectra and mid-resolution infrared spectra obtained with NASA Infrared Telescope Facility/SpeX. The core mass of TOI-519 b inferred from a thermal evolution model ranges from 0 to ∼30 M⊕, which can be explained by both core accretion and disk instability models as the formation origins of this planet. However, TOI-519 is in line with the emerging trend that M dwarfs with close-in giant planets tend to have high metallicity, which may indicate that they formed in the core accretion model. The system is also consistent with the potential trend that close-in giant planets around M dwarfs tend to be less massive than those around FGK dwarfs.