The planetary system around HD 190622 (TOI-1054)

Measuring the gas content of low-mass planets orbiting F-stars^{★,★★,★★★}

¹ Institute of Planetary Research, German Aerospace Center (DLR), Rutherfordstrasse 2, 12489 Berlin, Germany
e-mail: juan.cabrera@dlr.de
² Dipartimento di Fisica, Universita degli Studi di Torino, via Pietro Giuria 1, 10125 Torino, Italy
³ Physikalisches Institut, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
⁴ Space Research Institute, Austrian Academy of Sciences, Schmiedl-strasse 6, 8042 Graz, Austria
⁵ Center for Space and Habitability, University of Bern, Gesellschaftsstrasse 6, 3012 Bern, Switzerland
⁶ Observatoire Astronomique de l’Université de Genève, Chemin Pegasi 51, 1290 Versoix, Switzerland
⁷ Department of Astronomy, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
⁸ Centre for Exoplanet Science, SUPA School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
⁹ Instituto de Astrofísica e Ciencias do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal
¹⁰ Astrobiology Research Unit, Université de Liège, Allée du 6-Août 19C, 4000 Liège, Belgium
¹¹ Space sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège, Allée du 6-Août 19C, 4000 Liège, Belgium
¹² Rheinisches Institut für Umweltforschung, Abt. Planetenforschung, an der Universität zu Köln, 50931 Cologne, Germany
¹³ Aix-Marseille Univ., CNRS, CNES, LAM, 38 rue Frédéric Joliot-Curie, 13388 Marseille, France
¹⁴ European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago de Chile, Chile
¹⁵ Instituto de Astrofísica de Canarias, c/Vía Láctea, s/n 38205 La Laguna, Tenerife, Spain
¹⁶ Departamento de Astrofísica, Universidad de La Laguna, Avenida Astrofísico Francisco Sánchez, s/n. Facultad de Ciencias, Sección de Física, Apartado 456, 38200 San Cristóbal de La Laguna, S/C de Tenerife, Spain
¹⁷ Institut de Ciències de l’Espai (ICE, CSIC), Campus UAB, Can Magrans s/n, 08193 Bellaterra, Spain
¹⁸ Institut d’Estudis Espacials de Catalunya (IEEC), Gran Capità, 2-4 Edifici Nexus, Desp. 201 08034 Barcelona, Spain
¹⁹ Admatis, 5. Kandó Kálmán Street, 3534 Miskolc, Hungary
²⁰ Sub-department of Astrophysics, Department of Physics, Clarendon Laboratory, Parks Road, University of Oxford, Oxford OX1 3PU, UK
²¹ Depto. de Astrofísica, Centro de Astrobiología (CSIC-INTA), ESAC campus, 28692 Villanueva de la Cañada (Madrid), Spain
²² Departamento de Física e Astronomia, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
²³ Université Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
²⁴ INAF, Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
²⁵ Zentrum für Astronomie und Astrophysik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany
²⁶ LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 5 place Jules Janssen, 92195 Meudon, France
²⁷ Université de Paris, Institut de physique du globe de Paris, CNRS, 1 Rue Jussieu, 75005 Paris, France
²⁸ Caltech/IPAC-NASA Exoplanet Science Institute Pasadena, CA, USA
²⁹ Center for Planetary Systems Habitability and McDonald Observatory, The University of Texas at Austin, 2305 Speedway Stop C116, Austin Texas 78712-1692, USA
³⁰ Center for Astrophysics, Harvard & Smithsonian, 60 Garden St, Cambridge, MA 02138, USA
³¹ Department of Physics and Astronomy, George Mason University, 4400 University Dr. Fairfax, VA 22030, USA
³² American Association of Variable Star Observers, 185 Alewife Brook Parkway, Suite 410, Cambridge, MA 02138, USA
³³ Centre for Mathematical Sciences, Lund University, Box 118, 221 00 Lund, Sweden
³⁴ Centre Vie dans l’Univers, Faculté des sciences, Université de Genève, Quai Ernest-Ansermet 30, CH-1211 Genève 4, Switzerland
³⁵ Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany
³⁶ Leiden Observatory, University of Leiden, PO Box 9513, 2300 RA Leiden, The Netherlands
³⁷ Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
³⁸ University of Vienna, Department of Astrophysics, Türkenschanzs-trasse 17, 1180 Vienna, Austria
³⁹ Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
⁴⁰ Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, UK
⁴¹ Science and Operations Department - Science Division (SCI-SC), Directorate of Science, European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Keplerlaan 1, 2201-AZ Noordwijk, The Netherlands
⁴² NASA Ames Research Center, Moffett Field, CA 94035, USA
⁴³ Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, 1121 Budapest, Konkoly Thege Miklós út 15-17, Hungary
⁴⁴ ELTE Eötvös Loránd University, Institute of Physics, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary
⁴⁵ Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
⁴⁶ IMCCE, UMR8028 CNRS, Observatoire de Paris, PSL Univ., Sorbonne Univ., 77 av. Denfert-Rochereau, 75014 Paris, France
⁴⁷ Institut d’Astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie, 98bis bld. Arago, 75014 Paris, France
⁴⁸ Department of Astronomy & Astrophysics, University of Chicago, Eckhardt, 5640 S Ellis Ave, Chicago IL 60637, USA
⁴⁹ Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
⁵⁰ Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 70 Vassar St, Cambridge MA 02139, USA
⁵¹ Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK
⁵² INAF, Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123 Catania, Italy
⁵³ Institute of Optical Sensor Systems, German Aerospace Center (DLR), Rutherfordstrasse 2, 12489 Berlin, Germany
⁵⁴ Dipartimento di Fisica e Astronomia “Galileo Galilei”, Universita degli Studi di Padova, Vicolo dell’Osservatorio 3, 35122 Padova, Italy
⁵⁵ ETH Zürich, Department of Physics, Wolfgang-Pauli-Strasse 2, 8093 Zürich, Switzerland
⁵⁶ ESTEC, European Space Agency, 2201AZ Noordwijk, NL, The Netherlands
⁵⁷ Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstraße 74-100, 12249 Berlin, Germany
⁵⁸ Astronomy Department and Van Vleck Observatory, Wesleyan University, 96 Foss Hill, Middletown, CT 06459, USA
⁵⁹ Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Ave Bldg 54, Cambridge MA 02139, USA
⁶⁰ Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, 77 Massachusetts Ave Bldg 54, Cambridge, MA 02139, USA
⁶¹ ELTE Eötvös Loránd University, Gothard Astrophysical Observatory, 9700 Szombathely, Szent Imre h. u. 112, Hungary
⁶² MTA-ELTE Exoplanet Research Group, 9700 Szombathely, Szent Imre h. u. 112, Hungary
⁶³ SETI Institute, 339 N Bernardo Ave Suite 200, Mountain View, CA 94043, USA
⁶⁴ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK
⁶⁵ Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544, USA

Received: 23 December 2022
Accepted: 25 April 2023

Abstract

Context. Giant planets are known to dominate the long-term stability of planetary systems due to their prevailing gravitational interactions, but they are also thought to play an important role in planet formation. Observational constraints improve our understanding of planetary formation processes such as the delivery of volatile-rich planetesimals from beyond the ice line into the inner planetary system. Additional constraints may come from studies of the atmosphere, but almost all such studies of the atmosphere investigate the detection of certain species, and abundances are not routinely quantitatively measured.

Aims. Accurate measurements of planetary bulk parameters – that is, mass and density – provide constraints on the inner structure and chemical composition of transiting planets. This information provides insight into properties such as the amounts of volatile species, which in turn can be related to formation and evolution processes.

Methods. The Transiting Exoplanet Survey Satellite (TESS) reported a planetary candidate around HD 190622 (TOI-1054), which was subsequently validated and found to merit further characterization with photometric and spectroscopic facilities. The KESPRINT collaboration used data from the High Accuracy Radial Velocity Planet Searcher (HARPS) to independently confirm the planetary candidate, securing its mass, and revealing the presence of an outer giant planet in the system. The CHEOPS consortium invested telescope time in the transiting target in order to reduce the uncertainty on the radius, improving the characterization of the planet.

Results. We present the discovery and characterization of the planetary system around HD 190622 (TOI-1054). This system hosts one transiting planet, which is smaller than Neptune (3.087_-0.053^+0.058R_Earth, 7.7 ± 1.0 M_Earth) but has a similar bulk density (1.43 ± 0.21 g cm⁻³) and an orbital period of 16 days; and a giant planet, not known to be transiting, with a minimum mass of 227.0 ± 6.7 M_Earth in an orbit with a period of 315 days.

Conclusions. Our measurements constrain the structure and composition of the transiting planet. HD 190622b has singular properties among the known population of transiting planets, which we discuss in detail. Among the sub-Neptune-sized planets known today, this planet stands out because of its large gas content.