TOI-954 b and K2-329 b: Short-period Saturn-mass Planets that Test whether Irradiation Leads to Inflation
Henning, Thomas; Vanderburg, Andrew; Bieryla, Allyson; Latham, David W.; Jordán, Andrés; Espinoza, Néstor; Brahm, Rafael; Tamura, Motohide; Kane, Stephen R.; Stassun, Keivan G.; Zhou, George; Bayliss, Daniel; Tan, Thiam-Guan; Wittenmyer, Robert A.; Crossfield, Ian J. M.; Horner, Jonathan; Ziegler, Carl; Collins, Karen A.; Ricker, George R.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Crane, Jeffrey D.; Shporer, Avi; Livingston, John H.; Narita, Norio; Nespral, David; Montet, Benjamin T.; Dragomir, Diana; Udry, Stéphane; Mann, Andrew W.; Rodriguez, Joseph E.; Penev, Kaloyan; Colón, Knicole D.; Jensen, Eric L. N.; Kielkopf, John F.; Huang, Chelsea X.; Hartman, Joel D.; Bakos, Gáspár Á.; Feinstein, Adina D.; Vanderspek, Roland K.; Ting, Eric B.; Bouchy, François; Nielsen, Louise D.; Plavchan, Peter; Mancini, Luigi; Schwarz, Richard P.; Matthews, Elisabeth C.; Sarkis, Paula; Krishnamurthy, Akshata; Okumura, Jack; Wright, Duncan J.; Zhang, Hui; Cloutier, Ryan; Díaz, Matías R.; Vezie, Michael; Teske, Johanna K.; Henze, Christopher E.; Burt, Jennifer A.; Addison, Brett C.; Mengel, Matthew W.; Villanueva, Steven; Rojas, Felipe; Torres, Pascal; Sha, Lizhou; Barbieri, Mauro; Hagelberg, Janis; Zapata, Abner; Drass, Holger; Hart, Rhodes; Ottoni, Gaël; Wang, Sharon; Snoddy, Erin
United States, Spain, Sweden, Chile, Switzerland, Canada, Japan, Australia, Hungary, United Kingdom, Germany, Italy, China
Abstract
We report the discovery of two short-period Saturn-mass planets, one transiting the G subgiant TOI-954 (TIC 44792534, V = 10.343, T = 9.78) observed in TESS sectors 4 and 5 and one transiting the G dwarf K2-329 (EPIC 246193072, V = 12.70, K = 10.67) observed in K2 campaigns 12 and 19. We confirm and characterize these two planets with a variety of ground-based archival and follow-up observations, including photometry, reconnaissance spectroscopy, precise radial velocity, and high-resolution imaging. Combining all available data, we find that TOI-954 b has a radius of ${0.852}_{-0.062}^{+0.053}\,{R}_{{\rm{J}}}$ and a mass of ${0.174}_{-0.017}^{+0.018}$ MJ and is in a 3.68 day orbit, while K2-329 b has a radius of ${0.774}_{-0.024}^{+0.026}\,{R}_{{\rm{J}}}$ and a mass of ${0.260}_{-0.022}^{+0.020}$ MJ and is in a 12.46 day orbit. As TOI-954 b is 30 times more irradiated than K2-329 b but more or less the same size, these two planets provide an opportunity to test whether irradiation leads to inflation of Saturn-mass planets and contribute to future comparative studies that explore Saturn-mass planets at contrasting points in their lifetimes.