Near-resonance in a system of sub-Neptunes from TESS
Creators: name: Quinn, Samuel N.
name: Becker, Juliette C.
name: Rodriguez, Joseph E.
name: Hadden, Sam
name: Huang, Chelsea X.
name: Morton, Timothy D.
name: Adams, Fred
name: Armstrong, David
name: Eastman, Jason D.
name: Horner, Jonathan
name: Kane, Stephen R.
name: Lissauer, Jack J.
name: Twicken, Joseph D.
name: Vanderburg, Andrew
name: Wittenmyer, Rob
name: Ricker, George R.
name: Vanderspek, Roland K.
name: Latham, David W.
name: Seager, Sara
name: Winn, Joshua N.
name: Jenkins, Jon M.
name: Agol, Eric
name: Barkaoui, Khalid
name: Beichman, Charles A.
name: Bouchy, François
name: Bouma, L. G.
name: Burdanov, Artem
name: Campbell, Jennifer
name: Carlino, Roberto
name: Cartwright, Scott M.
name: Charbonneau, David
name: Christiansen, Jessie L.
name: Ciardi, David
name: Collins, Karen A.
name: Collins, Kevin I.
name: Conti, Dennis M.
name: Crossfield, Ian J. M.
name: Daylan, Tansu
name: Dittmann, Jason
name: Doty, John
name: Dragomir, Diana
name: Ducrot, Elsa
name: Gillon, Michael
name: Glidden, Ana
name: Goeke, Robert F.
name: Gonzales, Erica J.
name: Hełminiak, Krzysztof G.
name: Horch, Elliott P.
name: Howell, Steve B.
name: Jehin, Emmanuel
name: Jensen, Eric L. N.
name: Kielkopf, John F.
name: Kristiansen, Martti H.
name: Law, Nicholas
name: Mann, Andrew W.
name: Marmier, Maxime
name: Matson, Rachel A.
name: Matthews, Elisabeth
name: Mazeh, Tsevi
name: Mori, Mayuko
name: Murgas, Felipe
name: Murray, Catriona
name: Narita, Norio
name: Nielsen, Louise D.
name: Ottoni, Gaël
name: Palle, Enric
name: Pawłaszek, Rafał
name: Pepe, Francesco
name: de Leon, Jerome Pitogo
name: Pozuelos, Francisco J.
name: Relles, Howard M.
name: Schlieder, Joshua E.
name: Sebastian, Daniel
name: Ségransan, Damien
name: Shporer, Avi
name: Stassun, Keivan G.
name: Tamura, Motohide
name: Tokovinin, Andrei
name: Udry, Stéphane
name: Waite, Ian
name: Ziegler, Carl
Publisher: name: arXiv
Year: 2019
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We report the Transiting Exoplanet Survey Satellite ($TESS$) 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 high signal-to-noise transit signals correspond to sub-Neptune-sized planets ($2.76$, $2.79$, and $2.94\ R_{\oplus}$), 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 high signal-to-noise ratio planet candidate. We also detect a candidate transiting super-Earth ($1.4\ R_{\oplus}$) with an orbital period of only $12.7$ hours and a candidate Neptune-sized planet ($4.2\ R_{\oplus}$) with a period of $13.28$ days, both at low signal-to-noise. 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 smaller 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.
description: Submitted to AAS Journals. 20 pages, 10 figures, 5 tables