TOI-3984 A b and TOI-5293 A b: Two Temperate Gas Giants Transiting Mid-M Dwarfs in Wide Binary Systems
Kobulnicky, Henry A.; Kowalski, Adam F.; Cochran, William D.; Mahadevan, Suvrath; Wisniewski, John; Everett, Mark E.; Colón, Knicole D.; Wang, Songhu; Monson, Andrew; Cañas, Caleb I.; Kanodia, Shubham; Ninan, Joe P.; Bender, Chad F.; Diddams, Scott A.; Fredrick, Connor; Halverson, Samuel; Ramsey, Lawrence W.; Robertson, Paul; Roy, Arpita; Schwab, Christian; Lin, Andrea S. J.; Beard, Corey; Libby-Roberts, Jessica; Stefánsson, Guđmundur; Gupta, Arvind F.; Parker, Brock A.; Powers, Luke; Jones, Sinclaire; Schutte, Maria; Zeimann, Gregory; Larsen, Alexander; Chapman, Franklin A. L.; Penprase, Bryan Edward
United States, Switzerland, India, Australia
Abstract
We confirm the planetary nature of two gas giants discovered by TESS to transit M dwarfs with stellar companions at wide separations. TOI-3984 A (J = 11.93) is an M4 dwarf hosting a short-period (4.353326 ± 0.000005 days) gas giant (M p = 0.14 ± 0.03 M J and R p = 0.71 ± 0.02 R J) with a wide-separation white dwarf companion. TOI-5293 A (J = 12.47) is an M3 dwarf hosting a short-period (2.930289 ± 0.000004 days) gas giant (M p = 0.54 ± 0.07 M J and R p = 1.06 ± 0.04 R J) with a wide-separation M dwarf companion. We characterize both systems using a combination of ground- and space-based photometry, speckle imaging, and high-precision radial velocities from the Habitable-zone Planet Finder and NEID spectrographs. TOI-3984 A b (T eq = 563 ± 15 K and $\mathrm{TSM}={138}_{-27}^{+29}$ ) and TOI-5293 A b ( ${T}_{\mathrm{eq}}={675}_{-30}^{+42}$ K and TSM = 92 ± 14) are two of the coolest gas giants among the population of hot Jupiter-sized gas planets orbiting M dwarfs and are favorable targets for atmospheric characterization of temperate gas giants and 3D obliquity measurements to probe system architecture and migration scenarios.