Architecture of TOI-561 planetary system

Author(s): G. Piotto, T. Zingales, L. Borsato, J. A. Egger, A. C.M. Correia, A. E. Simon, H. G. Florén, S. G. Sousa, P. F.L. Maxted, D. Nardiello, L. Malavolta, T. G. Wilson, Y. Alibert, V. Adibekyan, A. Bonfanti, R. Luque, N. C. Santos, M. J. Hooton, L. Fossati, A. M.S. Smith, S. Salmon, G. Lacedelli, R. Alonso, T. Bárczy, D. Barrado Navascues, S. C.C. Barros, W. Baumjohann, T. Beck, W. Benz, N. Billot, A. Brandeker, C. Broeg, M. Buder, A. Collier Cameron, Sz Csizmadia, P. E. Cubillos, M. B. Davies, M. Deleuil, A. Deline, O. D.S. Demangeon, B. O. Demory, A. Derekas, B. Edwards, D. Ehrenreich, A. Erikson, A. Fortier, M. Fridlund, D. Gandolfi, K. Gazeas, M. Gillon, M. Güdel, M. N. Günther, A. Heitzmann, Ch Helling, K. G. Isaak, L. L. Kiss, J. Korth, K. W.F. Lam, J. Laskar, A. Lecavelier Des Etangs, M. Lendl, P. Leonardi, D. Magrin, G. Mantovan, C. Mordasini, V. Nascimbeni, G. Olofsson, I. Pagano, E. Pallé, G. Peter, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, F. Ratti, H. Rauer, I. Ribas, G. Scandariato, D. Ségransan, D. Sicilia, M. Stalport, S. Sulis, Gy M. Szabó, S. Udry, S. Ulmer-Moll, V. Van Grootel, J. Venturini, E. Villaver, N. A. Walton, J. N. Winn, S. Wolf
Abstract: We present new observations from CHEOPS (CHaracterising ExOPlanet Satellite) and TESS (Transiting Exoplanet Survey Satellite) to clarify the architecture of the planetary system hosted by the old Galactic thick disc star TOI-561. Our global analysis, which also includes previously published photometric and radial velocity data, incontrovertibly proves that TOI-561 is hosting at least four transiting planets with periods of 0.44 d (TOI-561 b), 10.8 d (TOI-561 c), 25.7 d (TOI-561 d), and 77.1 d (TOI-561 e) and a fifth non-transiting candidate, TOI-561f with a period of 433 d. The precise characterization of TOI-561's orbital architecture is interesting since old and metal-poor thick disc stars are less likely to host ultrashort-period super-Earths like TOI-561 b. The new period of planet -e is consistent with the value obtained using radial velocity alone and is now known to be 77.14399 ± 0.00025 d, thanks to the new CHEOPS and TESS transits. The new data allowed us to improve its radius (R_p = 2.517 ± 0.045 R_⊕ from 5 per cent to 2 per cent precision) and mass(M_p = 12.4 ± 1.4 M_?) estimates, implying a density of ρ_p = 0.778 ± 0.097 ρ_⊕. Thanks to recent TESS observations and the focused CHEOPS visit of the transit of TOI-561 e, a good candidate for exomoon searches, the planet's period is finally constrained, allowing us to predict transit times through 2030 with 20-min accuracy. We present an updated version of the internal structure of the four transiting planets. We finally performed a detailed stability analysis, which confirmed the long-term stability of the outer planet TOI-561 f.
Organisation(s): Department of Astrophysics
External organisation(s): University of Padova, Osservatorio Astronomico, Universität Bern, Universidade de Coimbra, Stockholm University, Universidade do Porto, Keele University, University of Warwick, Österreichische Akademie der Wissenschaften (ÖAW), University of Chicago, University of Cambridge, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Université de Genève, Institute of Astrophysics of the Canary Islands, University of La Laguna, Admatis Ltd., European Space Astronomy Centre (ESA), University of St. Andrews, INAF-Osservatorio Astrofisico di Torino, Lund University, Aix-Marseille Université, Eötvös Loránd University Budapest, SRON Netherlands Institute for Space Research , Leiden University, Chalmers University of Technology, University of Turin, National & Kapodistrian University of Athens, Université de Liège, Science and Operations Department - Science Division (SCI-SC), Technische Universität Graz, Eötvös Loránd Research Network, Lund Observatory, Université de recherche Paris Sciences et Lettres, Université Paris VI - Pierre-et-Marie-Curie, Università degli Studi di Trento, INAF-Osservatorio Astrofisico di Catania, Eidgenössische Technische Hochschule Zürich, Freie Universität Berlin (FU), Spanish National Research Council (CSIC), Institute of Space Studies of Catalonia (IEEC), HUN-REN-ELTE Exoplanet Research Group, Princeton University
Journal: Monthly Notices of the Royal Astronomical Society
Volume: 535
Pages: 2763-2774
No. of pages: 12
ISSN: 0035-8711
DOI: https://doi.org/10.1093/mnras/stae2440
Publication date: 12-2024
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy, 103004 Astrophysics
Keywords
ASJC Scopus subject areas: Astronomy and Astrophysics, Space and Planetary Science
Portal url: https://ucrisportal.univie.ac.at/en/publications/613a1872-3534-425e-baf3-861e8eaa902b

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