Three Saturn-mass planets transiting F-type stars revealed with TESS and HARPS

TOI-615b, TOI-622b, and TOI-2641b^★

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 Astrophysics Group, Keele University, Staffordshire ST5 5BG, 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 Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Bd de l’Observatoire, CS 34229, 06304 Nice cedex 4, France
⁷ Physikalisches Institut, University of Bern, Gesellschaftsstrasse 6, 3012 Bern, Switzerland
⁸ Astrobiology Research Unit, Université de Liège, 19C Allée du 6 Août, 4000 Liège, Belgium
⁹ Department of Earth, Atmospheric and Planetary Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
¹⁰ Instituto de Astrofísica de Canarias (IAC), Calle Vía Láctea s/n, 38200 La Laguna, Tenerife, Spain
¹¹ Center for Data Intensive and Time Domain Astronomy, Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
¹² Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK
¹³ El Sauce Observatory, Río Hurtado, Coquimbo Province, Chile
¹⁴ University of Southern Queensland, Centre for Astrophysics, West Street, Toowoomba QLD 4350, Australia
¹⁵ Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
¹⁶ Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
¹⁷ University of Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
¹⁸ Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CauP, Rua das Estrelas, 4150-762 Porto, Portugal
¹⁹ Department of Physics, Engineering and Astronomy, Stephen F. Austin State University, 1936 North St, Nacogdoches, TX 75962, USA
²⁰ Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
²¹ Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
²² SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
²³ Facultad de Ingeniera y Ciencias, Universidad Adolfo Ibáñez, Av. Diagonal las Torres 2640, Peñalolén, Santiago, Chile
²⁴ Millennium Institute for Astrophysics, Faculty of Physics, Campus San Joaquin UC, Av. Vicuna Mackenna, 4860 Mascul, Santiago, Chile
²⁵ Data Observatory Foundation, Eliodoro Yáñez, 2990 Providencia, Santiago, Chile
²⁶ European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla, 19001 Santiago, Chile
²⁷ NASA Ames Research Center, Moffett Field, CA 94035, USA
²⁸ Swinburne University of Technology, Centre for Astrophysics and Supercomputing, John Street, Hawthorn, VIC 3122, Australia
²⁹ Cerro Tololo Inter-American Observatory/NSF’s NOIRLab, Casilla 603, La Serena, Chile
³⁰ Astrophysics Group, Cavendish Laboratory, J.J. Thomson Avenue, Cambridge CB3 0HE, UK
³¹ George Mason University, 4400 University Drive, Fairfax, VA 22030, USA
³² Department of Extrasolar Planets and Atmospheres, Institute of Planetary Research, German Aerospace Center (DLR), Rutherfordstraße 2, 12489 Berlin, Germany
³³ Bryant Space Science Center, Department of Astronomy, University of Florida, Gainesville, FL 32611, USA
³⁴ University of Maryland, Baltimore County, Baltimore, MD 21250, USA
³⁵ NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771, USA
³⁶ Space Research Institute, Austrian Academy of Sciences, Schmiedl-straße 6, 8042 Graz, Austria
³⁷ Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255, USA
³⁸ European Southern Observatory, Karl-Schwarzschild-Strae 2, 85748 Garching bei München, Germany
³⁹ South African Astronomical Observatory, PO Box 9, Observatory, Cape Town 7935, South Africa
⁴⁰ School of Physics & Astronomy, University of Birmingham, Edg-baston, Birmingham B15 2TT, UK
⁴¹ Department of Electrical Engineering and Center of Astro Engineering, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Santiago, Chile
⁴² Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago, Chile
⁴³ Astrophysics Research Centre, Queen’s University Belfast, Belfast BT7 1NN, UK

Received: 14 March 2023
Accepted: 2 May 2023

Abstract

While the sample of confirmed exoplanets continues to grow, the population of transiting exoplanets around early-type stars is still limited. These planets allow us to investigate the planet properties and formation pathways over a wide range of stellar masses and study the impact of high irradiation on hot Jupiters orbiting such stars. We report the discovery of TOI-615b, TOI-622b, and TOI-2641b, three Saturn-mass planets transiting main sequence, F-type stars. The planets were identified by the Transiting Exoplanet Survey Satellite (TESS) and confirmed with complementary ground-based and radial velocity observations. TOI-615b is a highly irradiated (~1277 F^⊕) and bloated Saturn-mass planet (1.69_−0.06^+0.05 R_Jup and 0.43_−0.08^+0.09 M_Jup) in a 4.66 day orbit transiting a 6850 K star. TOI-622b has a radius of 0.82_−0.03^+0.03 R_Jup and a mass of 0.30_−0.08^+0.07 M_Jup in a 6.40 day orbit. Despite its high insolation flux (~600 F^⊕), TOI-622b does not show any evidence of radius inflation. TOI-2641b is a 0.39_−0.04^+0.02 M_Jup planet in a 4.88 day orbit with a grazing transit (b = 1.04_−0.06^+0.05) that results in a poorly constrained radius of 1.61_−0.64^+0.46 R_Jup. Additionally, TOI-615b is considered attractive for atmospheric studies via transmission spectroscopy with ground-based spectrographs and JWST. Future atmospheric and spin-orbit alignment observations are essential since they can provide information on the atmospheric composition, formation, and migration of exoplanets across various stellar types.