A long-period transiting substellar companion in the super-Jupiters to brown dwarfs mass regime and a prototypical warm-Jupiter detected by TESS^★

¹ European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla, 19001 Santiago, Chile
e-mail: mjones@eso.org
² Instituto de Astronomía, Universidad Católica del Norte, Angamos 0610, 1270709 Antofagasta, Chile
³ Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Av. Diagonal las Torres 2640, Peñalolén, Santiago, Chile
⁴ Millennium Institute for Astrophysics, Santiago, Chile
⁵ Data Observatory Foundation, Santiago, Chile
⁶ Institute of Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
⁷ Department of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA, 16802, USA
⁸ Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA, 16802, USA
⁹ Department of Physics, Engineering and Astronomy, Stephen F. Austin State University, 1936 North St, Nacogdoches, TX 75962, USA
¹⁰ Cerro Tololo Inter-American Observatory, Casilla 603, La Serena, Chile
¹¹ Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255, USA
¹² Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Santiago, Chile
¹³ Department of Physics & Astronomy, College of Charleston, 66 George Street Charleston, SC 29424, USA
¹⁴ School of Physics & Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
¹⁵ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
¹⁶ Department of Astronomy, Sofia University “St Kliment Ohridski”, 5 James Bourchier Blvd, BG-1164 Sofia, Bulgaria
¹⁷ Steward Observatory and Department of Astronomy, The University of Arizona, Tucson, AZ 85721, USA
¹⁸ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
¹⁹ Wesleyan University, Middletown, CT 06459, USA
²⁰ Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
²¹ European Space Agency (ESA), European Space Astronomy Centre (ESAC), Camino Bajo del Castillo s/n, 28692 Villanueva de la Canada, Madrid, Spain
²² Department of Astronomy, The Ohio State University, Columbus, OH 43210, USA
²³ Observatoire Astronomique de l’Université de Genève, Chemin Pegasi 51, 1290 Versoix, Switzerland
²⁴ Physikalisches Institut, University of Bern, Gesellschaftsstrasse 6, 3012 Bern, Switzerland
²⁵ Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA
²⁶ Astrobiology Research Unit, University of Liège, Allée du 6 août 19, 4000 Liège (Sart-Tilman), Belgium
²⁷ AIM, CEA, CNRS, Université Paris-Saclay, Université de Paris, 91191 Gif-sur-Yvette, France
²⁸ Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, UK
²⁹ Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 2, 8093 Zurich, Switzerland
³⁰ NASA Ames Research Center, Moffett Field, CA 94035, USA
³¹ SETI Institute, Mountain View, CA 94043 USA
³² Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
³³ Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
³⁴ Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
³⁵ El Sauce Observatory – Obstech, Río Hurtado, Coquimbo Region, Chile
³⁶ NASA Exoplanet Science Institute, Caltech/IPAC, Mail Code 100-22,1200 E. California Blvd., Pasadena, CA 91125, USA

Received: 3 October 2023
Accepted: 9 January 2024

Abstract

We report on the confirmation and follow-up characterization of two long-period transiting substellar companions on low-eccentricity orbits around TIC 4672985 and TOI-2529, whose transit events were detected by the TESS space mission. Ground-based photometric and spectroscopic follow-up from different facilities, confirmed the substellar nature of TIC 4672985 b, a massive gas giant in the transition between the super-Jupiters and brown dwarfs mass regime. From the joint analysis we derived the following orbital parameters: P = 69.0480_−0.0005^+0.0004 d, M_p = 12.74_−1.01^+1.01 M_j, R_p = 1.026_−0.067^+0.065 R_j and e = 0.018_−0.004^+0.004. In addition, the RV time series revealed a significant trend at the ~350 m s⁻¹ yr⁻¹ level, which is indicative of the presence of a massive outer companion in the system. TIC 4672985 b is a unique example of a transiting substellar companion with a mass above the deuterium-burning limit, located beyond 0.1 AU and in a nearly circular orbit. These planetary properties are difficult to reproduce from canonical planet formation and evolution models. For TOI-2529 b, we obtained the following orbital parameters: P = 64.5949_−0.0003^+0.0003 d, M_p = 2.340_−0.195^+0.197 M_j, R_p = 1.030_−0.050^+0.050 R_j and e = 0.021_−0.015^+0.024, making this object a new example of a growing population of transiting warm giant planets.