Three new brown dwarfs and a massive hot Jupiter revealed by TESS around early-type stars^★

¹ Observatoire de Genève, Université de Genève, Chemin Pegasi, 51, 1290 Versoix, Switzerland
e-mail: angeliki.psaridi@unige.ch
² Vanderbilt University, Department of Physics & Astronomy, 6301 Stevenson Center Lane, Nashville, TN 37235 USA
³ Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ UK
⁴ Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL UK
⁵ Centre for Exoplanets and Habitability, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL UK
⁶ Núcleo de Astronomía, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejército 441, Santiago, Chile
⁷ Department of Astronomy, Tsinghua University, 100084 Beijing, PR China
⁸ Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
⁹ Harvard University, Cambridge, MA 02138 USA
¹⁰ Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Av. Diagonal las Torres 2640, Peñalolén, Santiago, Chile
¹¹ Millennium Institute for Astrophysics, Chile
¹² NASA Exoplanet Science Institute, Caltech/IPAC, Mail Code 100-22, 1200 E. California Blvd., Pasadena, CA 91125 USA
¹³ Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045 USA
¹⁴ Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE UK
¹⁵ NASA Ames Research Center, Moffett Field, CA 94035 USA
¹⁶ University of Grenoble Alpes, CNRS, IPAG, Grenoble, 38000 France
¹⁷ Centro de Astrofísica y Tecnologías Afines (CATA), Casilla 36-D, Santiago, Chile
¹⁸ Center for Astrophysics, Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138 USA
¹⁹ Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 USA
²⁰ Centre for Astrophysics, University of Southern Queensland, Toowoomba, QLD 4350 Australia
²¹ Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138 USA
²² George Mason University, 4400 University Drive, Fairfax, VA 22030 USA
²³ Department of Astronomy, University of California Berkeley, Berkeley, CA 94720 USA
²⁴ El Sauce Observatory, Coquimbo Province, Chile
²⁵ Department of Physics and Astronomy, University of New Mexico, 210 Yale Blvd NE, Albuquerque, NM 87106 USA
²⁶ University of Zürich, Institute for Computational Science, Winterthurerstrasse 190, 8057 Zurich, Switzerland
²⁷ Brierfield Observatory, New South Wales, Australia
²⁸ NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA
²⁹ Patashnick Voorheesville Observatory, Voorheesville, NY 12186 USA
³⁰ Kotizarovci Observatory, Sarsoni 90, 51216 Viskovo, Croatia
³¹ Hazelwood Observatory, Australia
³² Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Bd de l’Observatoire, CS 34229, 06304 Nice cedex 4, France

Received: 2 March 2022
Accepted: 25 April 2022

Abstract

Context. The detection and characterization of exoplanets and brown dwarfs around massive AF-type stars is essential to investigate and constrain the impact of stellar mass on planet properties. However, such targets are still poorly explored in radial velocity (RV) surveys because they only feature a small number of stellar lines and those are usually broadened and blended by stellar rotation as well as stellar jitter. As a result, the available information about the formation and evolution of planets and brown dwarfs around hot stars is limited.

Aims. We aim to increase the sample and precisely measure the masses and eccentricities of giant planets and brown dwarfs transiting early-type stars detected by the Transiting Exoplanet Survey Satellite (TESS).

Methods. We followed bright (V < 12 mag) stars with T_eff > 6200 K that host giant companions (R > 7 R_⊕) using ground-based photometric observations as well as high precision radial velocity measurements from the CORALIE, CHIRON, TRES, FEROS, and MINERVA-Australis spectrographs.

Results. In the context of the search for exoplanets and brown dwarfs around early-type stars, we present the discovery of three brown dwarf companions, TOI-629b, TOI-1982b, and TOI-2543b, and one massive planet, TOI-1107b. From the joint analysis of TESS and ground-based photometry in combination with high precision radial velocity measurements, we find the brown dwarfs have masses between 66 and 68 M_Jup, periods between 7.54 and 17.17 days, and radii between 0.95 and 1.11 R_Jup. The hot Jupiter TOI-1107b has an orbital period of 4.08 days, a radius of 1.30 R_Jup, and a mass of 3.35 M_Jup. As a by-product of this program, we identified four low-mass eclipsing components (TOI-288b, TOI-446b, TOI-478b, and TOI-764b).

Conclusions. Both TOI-1107b and TOI-1982b present an anomalously inflated radius with respect to the age of these systems. TOI-629 is among the hottest stars with a known transiting brown dwarf. TOI-629b and TOI-1982b are among the most eccentric brown dwarfs. The massive planet and the three brown dwarfs add to the growing population of well-characterized giant planets and brown dwarfs transiting AF-type stars and they reduce the apparent paucity.