The SOPHIE search for northern extrasolar planets

XVIII. Six new cold Jupiters, including one of the most eccentric exoplanet orbits^★

¹ Instituto de Astrofísica e Ciências do Espaço, CAUP, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
e-mail: olivier.demangeon@astro.up.pt
² Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
³ Institut d’Astrophysique de Paris, 98 bis, boulevard Arago, 75014 Paris, France
⁴ Observatoire de Haute-Provence, CNRS, Université d’Aix-Marseille, 04870 Saint-Michel-l’Observatoire, France
⁵ LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, 5 place Jules Janssen, 92195 Meudon, France
⁶ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
⁷ Aix-Marseille Univ, CNRS, CNES, LAM, Marseille, France
⁸ Univ. de Toulouse, CNRS, IRAP, 14 Avenue Belin, 31400 Toulouse, France
⁹ Laboratoire J.-L. Lagrange, Observatoire de la Côte d’Azur (OCA), Universite de Nice-Sophia Antipolis (UNS), CNRS, Campus Valrose, 06108 Nice Cedex 2, France
¹⁰ Observatoire de Genève, Université de Genève, Chemin Pegasi, 51, 1290 Sauverny, Switzerland
¹¹ RHEA Group for the European Space Agency (ESA), European Space Astronomy Centre (ESAC), Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
¹² Departamento de Matemática y Física Aplicadas, Universidad Católica de la Santísima Concepción, Alonso de Rivera 2850, Concepción, Chile
¹³ Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, Chile
¹⁴ Millennium Institute of Astrophysics, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago, Chile
¹⁵ Las Campanas Observatory, Carnegie Institution of Washington, Colina el Pino, Casilla 601 La Serena, Chile
¹⁶ International Center for Advanced Studies (ICAS) and ICIFI (CONICET), ECyT-UNSAM, Campus Miguelete, 25 de Mayo y Francia, (1650) Buenos Aires, Argentina
¹⁷ Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
¹⁸ Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany
¹⁹ INAF – Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
²⁰ Department of Physics, Shahid Beheshti University, Tehran, Iran
²¹ Mbarara University of Science and Technology, PO Box 1410, Mbarara, Uganda

Received: 14 April 2021
Accepted: 14 June 2021

Abstract

Context. Due to their low transit probability, the long-period planets are, as a population, only partially probed by transit surveys. Radial velocity surveys thus have a key role to play, in particular for giant planets. Cold Jupiters induce a typical radial velocity semi-amplitude of 10 m s⁻¹, which is well within the reach of multiple instruments that have now been in operation for more than a decade.

Aims. We take advantage of the ongoing radial velocity survey with the SOPHIE high-resolution spectrograph, which continues the search started by its predecessor ELODIE to further characterize the cold Jupiter population.

Methods. Analyzing the radial velocity data from six bright solar-like stars taken over a period of up to 15 yr, we attempt the detection and confirmation of Keplerian signals.

Results. We announce the discovery of six planets, one per system, with minimum masses in the range 4.8–8.3 M_jup and orbital periods between 200 days and 10 yr. The data do not provide enough evidence to support the presence of additional planets in any of these systems. The analysis of stellar activity indicators confirms the planetary nature of the detected signals.

Conclusions. These six planets belong to the cold and massive Jupiter population, and four of them populate its eccentric tail. In this respect, HD 80869 b stands out as having one of the most eccentric orbits, with an eccentricity of 0.862_−0.018^+0.028. These planets can thus help to better constrain the migration and evolution processes at play in the gas giant population. Furthermore, recent works presenting the correlation between small planets and cold Jupiters indicate that these systems are good candidates to search for small inner planets.