TOI-530b: a giant planet transiting an M-dwarf detected by TESS
Barclay, Thomas; Latham, David W.; Bedell, Megan; Stassun, Keivan G.; Schlieder, Joshua E.; Howell, Steve B.; Howard, Andrew W.; Crossfield, Ian J. M.; Collins, Karen A.; Ricker, George R.; Vanderspek, Roland; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Shporer, Avi; Ciardi, David R.; Livingston, John H.; Fukui, Akihiko; Narita, Norio; Palle, Enric; Rackham, Benjamin V.; Evans, Phil; Gan, Tianjun; Matson, Rachel A.; Giacalone, Steven; Dressing, Courtney D.; Charbonneau, David; Mao, Shude; Gonzales, Erica J.; Scott, Nicholas J.; Murgas, Felipe; Wang, Sharon Xuesong; Vezie, Michael; Kawauchi, Kiyoe; Gnilka, Crystal L.; Fouqué, Pascal; Parviainen, Hannu; Esparza-Borges, Emma; Isogai, Keisuke; Christiansen, Jessie; Arnold, Luc; Rodriguez, David R.; Kurita, Seiya; Rose, Mark; Fan, Jiahao; Lin, Zitao; Rudat, Alexander; Elliott, Ashley; Liu, Beibei
China, United States, France, Japan, Spain, Chile
Abstract
We report the discovery of TOI-530b, a transiting Saturn-like planet around an M0.5V dwarf, delivered by the Transiting Exoplanet Survey Satellite (TESS). The host star is located at a distance of 147.7 ± 0.6 pc with a radius of R* = 0.54 ± 0.03 R⊙ and a mass of M* = 0.53 ± 0.02 M⊙. We verify the planetary nature of the transit signals by combining ground-based multiwavelength photometry, high-resolution spectroscopy from SPIRou as well as high-angular-resolution imaging. With V = 15.4 mag, TOI-530b is orbiting one of the faintest stars accessible by ground-based spectroscopy. Our model reveals that TOI-530b has a radius of 0.83 ± 0.05 RJ and a mass of 0.37 ± 0.08 MJ on a 6.39-d orbit. TOI-530b is the sixth transiting giant planet hosted by an M-type star, which is predicted to be infrequent according to core accretion theory, making it a valuable object to further study the formation and migration history of similar planets. Furthermore, we identify a potential dearth of hot massive giant planets around M-dwarfs with separation distance smaller than 0.1 au and planet-to-star mass ratio between 2 × 10-3 and 10-2. We also find a possible correlation between hot giant planet formation and the metallicity of its parent M-dwarf. We discuss the potential formation channel of such systems.