Near-resonance in a System of Sub-Neptunes from TESS
Kristiansen, Martti H.; Vanderburg, Andrew; Latham, David W.; Quinn, Samuel N.; Tamura, Motohide; Morton, Timothy D.; Kane, Stephen R.; Stassun, Keivan G.; Schlieder, Joshua E.; Howell, Steve B.; Crossfield, Ian J. M.; Horner, Jonathan; Ziegler, Carl; Lissauer, Jack J.; Collins, Karen A.; Ricker, George R.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Beichman, Charles A.; Adams, Fred C.; Mazeh, Tsevi; Barkaoui, Khalid; Shporer, Avi; Collins, Kevin I.; Narita, Norio; Palle, Enric; Dragomir, Diana; Udry, Stéphane; Mann, Andrew W.; Ducrot, Elsa; Winters, Jennifer G.; Rodriguez, Joseph E.; Eastman, Jason D.; Jensen, Eric L. N.; Kielkopf, John F.; Huang, Chelsea X.; Twicken, Joseph D.; Pozuelos, Francisco J.; Daylan, Tansu; Bouma, L. G.; Matthews, Elisabeth; Vanderspek, Roland K.; Matson, Rachel A.; Relles, Howard M.; Bouchy, François; Nielsen, Louise D.; Charbonneau, David; Pepe, Francesco; Horch, Elliott P.; Gonzales, Erica J.; Murgas, Felipe; Carlino, Roberto; Cartwright, Scott M.; Christiansen, Jessie L.; Doty, John; Law, Nicholas; Goeke, Robert F.; Glidden, Ana; Becker, Juliette C.; Conti, Dennis M.; Agol, Eric; Dittmann, Jason; Hełminiak, Krzysztof G.; Gillon, Michael; Jehin, Emmanuel; Mori, Mayuko; Ségransan, Damien; Burdanov, Artem; Ciardi, David; Hadden, Sam; Murray, Catriona; Sebastian, Daniel; Marmier, Maxime; Wittenmyer, Rob; Armstrong, David; Campbell, Jennifer; Ottoni, Gaël; Pawłaszek, Rafał; Pitogo de Leon, Jerome; Waite, Ian
United States, United Kingdom, Australia, Morocco, Belgium, Switzerland, Poland, Denmark, Israel, Japan, Spain, Canada
Abstract
We report the Transiting Exoplanet Survey Satellite detection of a multi-planet system orbiting the V = 10.9 K0 dwarf TOI-125. We find evidence for up to five planets, with varying confidence. Three transit signals with high signal-to-noise ratio correspond to sub-Neptune-sized planets (2.76, 2.79, and 2.94 R ⊕), and we statistically validate the planetary nature of the two inner planets (P b = 4.65 days, P c = 9.15 days). With only two transits observed, we report the outer object (P .03 = 19.98 days) as a planet candidate with high signal-to-noise ratio. We also detect a candidate transiting super-Earth (1.4 R ⊕) with an orbital period of only 12.7 hr and a candidate Neptune-sized planet (4.2 R ⊕) with a period of 13.28 days, both at low signal-to-noise ratio. This system is amenable to mass determination via radial velocities and transit-timing variations, and provides an opportunity to study planets of similar size while controlling for age and environment. The ratio of orbital periods between TOI-125 b and c (P c /P b = 1.97) is slightly lower than an exact 2:1 commensurability and is atypical of multiple planet systems from Kepler, which show a preference for period ratios just wide of first-order period ratios. A dynamical analysis refines the allowed parameter space through stability arguments and suggests that despite the nearly commensurate periods, the system is unlikely to be in resonance.