A warm super-Neptune around the G-dwarf star TOI-1710 revealed with TESS, SOPHIE, and HARPS-N

¹ Institut d’astrophysique de Paris, CNRS, UMR 7095 & Sorbonne Université, UPMC Paris 6, 98bis Bd Arago, 75014 Paris, France
² European Southern Observatory, Karl-Schwarzschild-Straße 2, 85748 Garching, Germany
e-mail: pkonig@eso.org
³ INAF - Osservatorio Astrofisico di Torino, via Osservatorio 20, 10025 Pino Torinese, Italy
⁴ Observatoire de Haute-Provence, CNRS, Université d’Aix-Marseille, 04870 Saint-Michel-l’Observatoire, France
⁵ Department of Physics, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
⁶ Department of Physics and Astronomy, University of Florence, Via Sansone 1, 50019 Sesto Fiorentino (FI), Italy
⁷ Aix-Marseille Université, CNRS, CNES, LAM, Marseille, France
⁸ INAF – Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monte Porzio Catone (RM), Italy
⁹ Instituto de Astrofisica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal
¹⁰ Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
¹¹ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
¹² Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA
¹³ INAF – Osservatorio Astronomico di Palermo, Piazza del Parlamento, 1, 90134 Palermo, Italy
¹⁴ Université Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
¹⁵ Fundación Galileo Galilei – INAF, Rambla José Ana Fernandez Pérez 7, 38712 Breña Baja, TF, Spain
¹⁶ Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, 38205 La Laguna, TF, Spain
¹⁷ Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, TF, Spain
¹⁸ INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
¹⁹ International Center for Advanced Studies and ICIFI (CONICET), ECyT-UNSAM, Campus Miguelete, 25 de Mayo y Francia, (1650) Buenos Aires, Argentina
²⁰ Department of Physics, Shahid Beheshti University, Tehran, Iran
²¹ Laboratoire J.-L. Lagrange, OCA, Université de Nice-Sophia Antipolis, CNRS, Campus Valrose, 06108 Nice Cedex 2, France
²² European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
²³ NASA Ames Research Center, Moffett Field, CA 94035, USA
²⁴ LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, Meudon, France
²⁵ Dip. di Fisica e Astronomia Galileo Galilei, Università di Padova, Vicolo dell’Osservatorio 2, 35122 Padova, Italy
²⁶ Max Planck Institute for Astronomy Königstuhl 17, 69117 Heidelberg, Germany
²⁷ Laboratório Nacional de Astrofísica, Rua Estados Unidos 154, 37504-364 Itajubá-MG, Brazil
²⁸ IRAP, Université de Toulouse, CNRS, UPS, CNES, 31400 Toulouse, France
²⁹ Department of Physics and Kavli Institute for Astrophysics and Space Research, MIT, Cambridge, MA 02139, USA
³⁰ Patashnick Voorheesville Observatory, Voorheesville, NY 12186, USA
³¹ Department of Earth, Atmospheric, and Planetary Sciences, MIT, Cambridge, MA 02139, USA
³² Department of Aeronautics and Astronautics, MIT, Cambridge, MA 02139, USA
³³ Dipartimento di Fisica, Università degli Studi di Torino, via Pietro Giuria 1, 10125 Torino, Italy
³⁴ Department of Physics, University of Warwick, Coventry CV4 7AL, UK
³⁵ Centre for Exoplanets and Habitability, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
³⁶ Department of Astrophysical Sciences, Peyton Hall, 4 Ivy Lane, Princeton, NJ 08544, USA
³⁷ George Mason University, 4400 University Drive, Fairfax, VA, 22030 USA

Received: 24 December 2021
Accepted: 13 April 2022

Abstract

We report the discovery and characterization of the transiting extrasolar planet TOI-1710 b. It was first identified as a promising candidate by the Transiting Exoplanet Survey Satellite. Its planetary nature was then established with SOPHIE and HARPS-N spectroscopic observations via the radial-velocity method. The stellar parameters for the host star are derived from the spectra and a joint Markov chain Monte-Carlo adjustment of the spectral energy distribution and evolutionary tracks of TOI-1710. A joint MCMC analysis of the TESS light curve and the radial-velocity evolution allows us to determine the planetary system properties. From our analysis, TOI-1710 b is found to be a massive warm super-Neptune (M_p = 28.3 ± 4.7 M_⊕ and R_p = 5.34 ± 0.11 R_⊕) orbiting a G5V dwarf star (T_eff = 5665 ± 55 K) on a nearly circular 24.3-day orbit (e = 0.16 ± 0.08). The orbital period of this planet is close to the estimated rotation period of its host star P_rot = 22.5 ± 2.0 days and it has a low Keplerian semi-amplitude K = 6.4 ± 1.0 m s⁻¹; we thus performed additional analyses to show the robustness of the retrieved planetary parameters. With a low bulk density of 1.03 ± 0.23 g cm⁻³ and orbiting a bright host star (J = 8.3, V = 9.6), TOI-1710 b is one of the best targets in this mass-radius range (near the Neptunian desert) for atmospheric characterization via transmission spectroscopy, a key measurement in constraining planet formation and evolutionary models of sub-Jovian planets.