Year: 2020
Type: article
Abstract: K2-146 is a cool, 0.358 dwarf that was found to host a mini-Neptune with a 2.67 day period. The planet exhibited strong transit timing variations (TTVs) of greater than 30 minutes, indicative of the presence of an additional object in the system. Here we report the discovery of the previously undetected outer planet in the system, K2-146 c, 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 ± 0.10 and a mass of 5.6 ± 0.7 , whereas K2-146 c has a radius of and a mass of 7.1 ± 0.9 . The inner and outer planets likely have moderate eccentricities of e = 0.14 ± 0.07 and 0.16 ± 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. We show that the resonance angles of the planet pair are librating, which may be an indication that K2-146 b and c are in a 3:2 mean motion resonance. The orbital architecture of the system points to a possible convergent migration origin.
Source: The Astronomical Journal
Authors: Kristine W. F. Lam, Judith Korth, Kento Masuda, Szilárd Csizmadia, Philipp Eigmüller, Gumundur Kári Stefánsson, Michael Endl, Simon Albrecht, Paul Robertson, Rafael Luque, John H. Livingston, Teruyuki Hirano, Roi Alonso Sobrino, Oscar Barragán, Juan Cabrera, Ilaria Carleo, Alexander Chaushev, William D. Cochran, Fei Dai, Jerome de Leon, Hans J. Deeg, Anders Erikson, Massimiliano Esposito, Malcolm Fridlund, Akihiko Fukui, Davide Gandolfi, Iskra Georgieva, Lucá Gonzalez Cuesta, Sascha Grziwa, Eike W. Guenther, Artie P. Hatzes, Diego Hidalgo, Maria Hjorth, Petr Kabath, Emil Knudstrup, Mikkel N. Lund, Suvrath Mahadevan, Savita Mathur, Pilar Montañes Rodríguez, Felipe Murgas, Norio Narita, David Nespral, Prajwal Niraula, Enric Palle, Martin Pätzold, Carina M. Persson, Jorge Prieto-Arranz, Heike Rauer, Seth Redfield, Ignasi Ribas, Marek Skarka, Alexis M. S. Smith, Jan Subjak, Vincent Van Eylen
Institutions: Technische Universität Berlin, University of Cologne, Rhenish Institute for Environmental Research, Princeton University, Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR), Pennsylvania State University, McDonald Observatory, The University of Texas at Austin, Aarhus University, Universidad de La Laguna, Instituto de Astrofísica de Canarias, The University of Tokyo, Tokyo Institute of Technology, University of Oxford, Wesleyan University, Massachusetts Institute of Technology, Thüringer Landessternwarte Tautenburg, Leiden University, Leiden Observatory, Chalmers University of Technology, National Institutes of Natural Sciences, National Astronomical Observatory of Japan, University of Turin, Czech Academy of Sciences, Czech Academy of Sciences, Astronomical Institute, Japan Science and Technology Agency, Astrobiology Center, Freie Universität Berlin, Institute of Space Sciences, Institut d'Estudis Espacials de Catalunya, Masaryk University, Charles University, University College London
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Aeronautics and Space Administration, Stellar Astrophysics Centre, European Space Agency, National Research Foundation, Deutsche Forschungsgemeinschaft, Danmarks Grundforskningsfond, Grantová Agentura České Republiky, Swedish National Space Agency, Danmarks Frie Forskningsfond, Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, Science and Technology Facilities Council, Japan Society for the Promotion of Science, National Research, Development and Innovation Office, Precursory Research for Embryonic Science and Technology
Awards: Search for Nearby, Small-sized Transiting Exoplanets and Study of Their Atmospheres, Understanding the Mass-Loss Mechanism of Close-in Exoplanets by Observations of Low-Mass Stars, G205717340, G3239502510, G3487714248, Uncovering the nature of small exoplanets via collaborations between observational and theoretical studies, G4167963696, G4211331249, G437073234, G4451527828, G4502305455, Tautenburg-Ondřejov radial velocity follow-up of transiting planetary systems, G5084423873, G5196914860, Astrophysics Consolidated Grant 2019-22, G5789749164, G5842135733, Exoplanets from space – CHEOPS and PLATO, ESA’s next two projects, G59402443, G6068113673, Astrophysics at Oxford 2019-2022, G6379254292, G6597422138, G6681768460, G6859194979, Astrophysics at Oxford 2016-2019, G7578079922, Search for Planets around Low-mass Stars: Uncovering the Diversity and Origin of Exoplanets, G8028352098, G8898318431, G8935584975
OpenAlex ID: W2963532838