A pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 characterized with CHEOPS

Author(s)

Thomas G. Wilson, Elisa Goffo, Yann Alibert, Davide Gandolfi, Andrea Bonfanti, Carina M. Persson, Andrew Collier Cameron, Malcolm Fridlund, Luca Fossati, Judith Korth, Willy Benz, Adrien Deline, Hans-Gustav Florén, Pascal Guterman, Vardan Adibekyan, Matthew J. Hooton, Sergio Hoyer, Adrien Leleu, Alexander James Mustill, Sébastien Salmon, Sérgio G. Sousa, Olga Suarez, Lyu Abe, Abdelkrim Agabi, Roi Alonso, Guillem Anglada, Joel Asquier, Tamas Bárczy, David Barrado y Navascues, Susana C. C. Barros, Wolfgang Baumjohann, Mathias Beck, Thomas Beck, Nicolas Billot, Xavier Bonfils, Alexis Brandeker, Christopher Broeg, Edward M. Bryant, Matthew R. Burleigh, Marco Buttu, Juan Cabrera, Sébastien Charnoz, David R. Ciardi, Ryan Cloutier, William D. Cochran, Karen A. Collins, Knicole D. Colón, Nicolas Crouzet, Szilard Csizmadia, Melvyn B. Davies, Magali Deleuil, Laetitia Delrez, Olivier Demangeon, Brice-Olivier Demory, Diana Dragomir, Georgina Dransfield, David Ehrenreich, Anders Erikson, Andrea Fortier, Tianjun Gan, Samuel Gill, Michaël Gillon, Crystal L. Gnilka, Nolan Grieves, Sascha Grziwa, Manuel Güdel, Tristan Guillot, Jonas Haldemann, Kevin Heng, Keith Horne, Steve B. Howell, Kate G. Isaak, Jon M. Jenkins, Eric L. N. Jensen, Laszlo Kiss, Gaia Lacedelli, Kristine Lam, Jacques Laskar, David W. Latham, Alain Lecavelier des Etangs, Monika Lendl, Kathryn V. Lester, Alan M. Levine, John Livingston, Christophe Lovis, Rafael Luque, Demetrio Magrin, Wenceslas Marie-Sainte, Pierre F. L. Maxted, Andrew W. Mayo, Brian McLean, Marko Mecina, Djamel Mékarnia, Valerio Nascimbeni, Louise D. Nielsen, Göran Olofsson, Hugh P. Osborn, Hannah L. M. Osborne, Roland Ottensamer, Isabella Pagano, Enric Pallé, Gisbert Peter, Giampaolo Piotto, Don Pollacco, Didier Queloz, Roberto Ragazzoni, Nicola Rando, Heike Rauer, Seth Redfield, Ignasi Ribas, George R. Ricker, Martin Rieder, Nuno C. Santos, Gaetano Scandariato, François-Xavier Schmider, Richard P. Schwarz, Nicholas J. Scott, Sara Seager, Damien Ségransan, Luisa Maria Serrano, Attila E. Simon, Alexis M. S. Smith, Manfred Steller, Chris Stockdale, Gyula Szabó, Nicolas Thomas, Eric B. Ting, Amaury H. M. J. Triaud, Stéphane Udry, Vincent Van Eylen, Valérie Van Grootel, Roland K. Vanderspek, Valentina Viotto, Nicholas Walton, Joshua N. Winn

Abstract

We report the discovery and characterization of a pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 (TIC 79748331), initially detected in the Transiting Exoplanet Survey Satellite (TESS) photometry. To characterize the system, we performed and retrieved the CHaracterising ExOPlanets Satellite (CHEOPS), TESS, and ground-based photometry, the High Accuracy Radial velocity Planet Searcher (HARPS) high-resolution spectroscopy, and Gemini speckle imaging. We characterize the host star and determine Teff,⋆=4734±67K⁠, R⋆=0.726±0.007R⊙⁠, and M⋆=0.748±0.032M⊙⁠. We present a novel detrending method based on point spread function shape-change modelling and demonstrate its suitability to correct flux variations in CHEOPS data. We confirm the planetary nature of both bodies and find that TOI-1064 b has an orbital period of Pb = 6.44387 ± 0.00003 d, a radius of Rb = 2.59 ± 0.04 R⊕, and a mass of Mb=13.5+1.7−1.8 M⊕, whilst TOI-1064 c has an orbital period of Pc=12.22657+0.00005−0.00004 d, a radius of Rc = 2.65 ± 0.04 R⊕, and a 3σ upper mass limit of 8.5 M⊕. From the high-precision photometry we obtain radius uncertainties of ∼1.6 per cent, allowing us to conduct internal structure and atmospheric escape modelling. TOI-1064 b is one of the densest, well-characterized sub-Neptunes, with a tenuous atmosphere that can be explained by the loss of a primordial envelope following migration through the protoplanetary disc. It is likely that TOI-1064 c has an extended atmosphere due to the tentative low density, however further radial velocities are needed to confirm this scenario and the similar radii, different masses nature of this system. The high-precision data and modelling of TOI-1064 b are important for planets in this region of mass–radius space, and it allow us to identify a trend in bulk density–stellar metallicity for massive sub-Neptunes that may hint at the formation of this population of planets.

Organisation(s)

Department of Astrophysics

External organisation(s)

Österreichische Akademie der Wissenschaften (ÖAW), Université de Genève, University of St. Andrews, University of Turin, Universität Bern, Chalmers University of Technology, Stockholm University, Science and Operations Department - Science Division (SCI-SC), Aix-Marseille Université, Universidade do Porto, Lund University, Université Côte d'Azur, Institute of Astrophysics of the Canary Islands, University of La Laguna, Universitat Autònoma de Barcelona , Admatis Ltd., Spanish National Research Council (CSIC), University of Grenoble Alpes, University of Warwick, University of Leicester, Concordia Research Station, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Université de Paris, California Institute of Technology (Caltech), Harvard-Smithsonian Center for Astrophysics, University of Texas, Austin, National Aeronautics & Space Administration (NASA), Université de Liège, University of New Mexico, University of Birmingham, Tsinghua University, NASA Ames Research Center, Swarthmore College, Hungarian Academy of Sciences, University of Padova, Sorbonne Université, Université Paris VI - Pierre-et-Marie-Curie, Massachusetts Institute of Technology, University of Tokyo, Instituto de Astrofísica de Andalucía (CSIC), Osservatorio Astronomico, Keele University, University of California, Berkeley, Space Telescope Science Institute, Universität zu Köln, University of Oxford, INAF-Osservatorio Astrofisico di Catania, University College London, Wesleyan University, Patashnick Voorheesville Observatory, Hazelwood Observatory, Eötvös Loránd University Budapest, University of Cambridge, Princeton University

Journal

Monthly Notices of the Royal Astronomical Society

Volume

511

Pages

1043–1071

No. of pages

29

ISSN

0035-8711

DOI

https://doi.org/10.1093/mnras/stab3799

Publication date

03-2022

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics, 103038 Space exploration

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/b15c2598-6b72-46fc-ba0d-27e75382c05a