Brown dwarf companion with a period of 4.6 yr interacting with the hot Jupiter CoRoT-20 b^★

¹ Observatoire Astronomique de l’Université de Genève, 51 Chemin des Maillettes, 1290 Versoix, Switzerland
e-mail: javiera.rey@unige.ch
² Aix Marseille Université, CNRS, Laboratoire d’Astrophysique de Marseille UMR 7326, 13388 Marseille Cedex 13, France
³ Institut d’Astrophysique de Paris, UMR 7095 CNRS, Université Pierre & Marie Curie, 98bis boulevard Arago, 75014 Paris, France
⁴ Observatoire de Haute Provence, CNRS, Aix Marseille Université, Institut Pythéas UMS 3470, 04870 Saint-Michel-l’Observatoire, France
⁵ Instituto de Astrofísica de Canarias, C. Via Lactea s/n, 38205 La Laguna, Tenerife, Spain
⁶ Universidad de La Laguna, Departamento de Astrofísica, 38206 La Laguna, Tenerife, Spain
⁷ INAF – Osservatorio Astrofisico di Torino, via Osservatorio 20, 10025 Pino Torinese, Italy
⁸ Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina
⁹ CONICET – Universidad de Buenos Aires, Instituto de Astronomía y Física del Espacio (IAFE), Buenos Aires, Argentina
¹⁰ Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
¹¹ Leiden Observatory, University of Leiden, PO Box 9513, 2300 RA Leiden, The Netherlands
¹² Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany
¹³ Université Côte d’Azur, OCA, CNRS, Nice, France
¹⁴ CNRS, Canada-France-Hawaii Telescope Corporation, 65-1238 Mamalahoa Hwy., Kamuela 96743, USA
¹⁵ Astrophysics Group, Cavendish Laboratory, J.J. Thomson Avenue, Cambridge CB3 0HE, UK
¹⁶ Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal

Received: 6 April 2018
Accepted: 27 June 2018

Abstract

We report the discovery of an additional substellar companion in the CoRoT-20 system based on six years of HARPS and SOPHIE radial velocity follow-up. CoRoT-20 c has a minimum mass of 17 ± 1 M_Jup and orbits the host star in 4.59 ± 0.05 yr, with an orbital eccentricity of 0.60 ± 0.03. This is the first identified system with an eccentric hot Jupiter and an eccentric massive companion. The discovery of the latter might be an indication of the migration mechanism of the hot Jupiter, via the Lidov–Kozai effect. We explore the parameter space to determine which configurations would trigger this type of interactions.