TOI-530b: a giant planet transiting an M-dwarf detected by TESS

March 2022 • 2022MNRAS.511...83G

Authors • Gan, Tianjun • Lin, Zitao • Wang, Sharon Xuesong • Mao, Shude • Fouqué, Pascal • Fan, Jiahao • Bedell, Megan • Stassun, Keivan G. • Giacalone, Steven • Fukui, Akihiko • Murgas, Felipe • Ciardi, David R. • Howell, Steve B. • Collins, Karen A. • Shporer, Avi • Arnold, Luc • Barclay, Thomas • Charbonneau, David • Christiansen, Jessie • Crossfield, Ian J. M. • Dressing, Courtney D. • Elliott, Ashley • Esparza-Borges, Emma • Evans, Phil • Gnilka, Crystal L. • Gonzales, Erica J. • Howard, Andrew W. • Isogai, Keisuke • Kawauchi, Kiyoe • Kurita, Seiya • Liu, Beibei • Livingston, John H. • Matson, Rachel A. • Narita, Norio • Palle, Enric • Parviainen, Hannu • Rackham, Benjamin V. • Rodriguez, David R. • Rose, Mark • Rudat, Alexander • Schlieder, Joshua E. • Scott, Nicholas J. • Vezie, Michael • Ricker, George R. • Vanderspek, Roland • Latham, David W. • Seager, Sara • Winn, Joshua N. • Jenkins, Jon M.

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.


IPAC Authors


Jessie Christiansen

Associate Scientist


David Ciardi

Senior Scientist