학술논문
It takes two planets in resonance to tango around K2-146
Document Type
Working Paper
Author
Lam, Kristine W. F.; Korth, Judith; Masuda, Kento; Csizmadia, Szilárd; Eigmüller, Philipp; Stefánsson, Guðmundur Kári; Endl, Michael; Albrecht, Simon; Luque, Rafael; Livingston, John H.; Hirano, Teruyuki; Sobrino, Roi Alonso; Barragán, Oscar; Cabrera, Juan; Carleo, Ilaria; Chaushev, Alexander; Cochran, William D.; Dai, Fei; de Leon, Jerome; Deeg, Hans J.; Erikson, Anders; Esposito, Massimiliano; Fridlund, Malcolm; Fukui, Akihiko; Gandolfi, Davide; Georgieva, Iskra; Cuesta, Lucá Gonzalez; Grziwa, Sascha; Guenther, Eike W.; Hatzes, Artie P.; Hidalgo, Diego; Hjorth, Maria; Kabath, Petr; Knudstrup, Emil; Lund, Mikkel N.; Mahadevan, Suvrath; Mathur, Savita; Rodríguez, Pilar Montañes; Murgas, Felipe; Narita, Norio; Nespral, David; Niraula, Prajwal; Palle, Enric; Pätzold, Martin; Persson, Carina M.; Prieto-Arranz, Jorge; Rauer, Heike; Redfield, Seth; Ribas, Ignasi; Robertson, Paul; Skarka, Marek; Smith, Alexis M. S.; Subjak, Jan; Van Eylen, Vincent
Source
Subject
Language
Abstract
K2-146 is a cool, 0.358 M_sun dwarf that was found to host a mini-Neptune with a 2.67-days period. The planet exhibited strong transit timing variations (TTVs) of greater than 30 minutes, indicative of the presence of a further object in the system. Here we report the discovery of the previously undetected outer planet, K2-146 c, in the system using additional photometric data. K2-146 c was found to have a grazing transit geometry and a 3.97-day period. The outer planet was only significantly detected in the latter K2 campaigns presumably because of precession of its orbital plane. The TTVs of K2-146 b and c were measured using observations spanning a baseline of almost 1200 days. We found strong anti-correlation in the TTVs, suggesting the two planets are gravitationally interacting. Our TTV and transit model analyses revealed that K2-146 b has a radius of 2.25 $\pm$ 0.10 \R_earth and a mass of 5.6 $\pm$ 0.7 M_earth, whereas K2-146 c has a radius of $2.59_{-0.39}^{+1.81}$ R_earth and a mass of 7.1 $\pm$ 0.9 M_earth. The inner and outer planets likely have moderate eccentricities of $e = 0.14 \pm 0.07$ and $0.16 \pm 0.07$, respectively. Long-term numerical integrations of the two-planet orbital solution show that it can be dynamically stable for at least 2 Myr. The evaluation of the resonance angles of the planet pair indicates that K2-146 b and c are likely trapped in a 3:2 mean motion resonance. The orbital architecture of the system points to a possible convergent migration origin.
Comment: 19 pages with 13 figures and 4 tables; Submitted
Comment: 19 pages with 13 figures and 4 tables; Submitted