TOI-1055 b

Author(s): A. Bonfanti, D. Gandolfi, J. A. Egger, L. Fossati, J. Cabrera, Andreas Krenn, Y. Alibert, W. Benz, N. Billot, H. G. Florén, M. Lendl, V. Adibekyan, S. Salmon, N. C. Santos, S. G. Sousa, T. G. Wilson, O. Barragán, A. Collier Cameron, L. Delrez, M. Esposito, E. Goffo, H. Osborne, H. P. Osborn, L. M. Serrano, V. Van Eylen, J. Alarcon, R. Alonso, G. Anglada, T. Bárczy, D. Barrado Navascues, S. C.C. Barros, W. Baumjohann, M. Beck, T. Beck, M. Bedell, X. Bonfils, L. Borsato, A. Brandeker, C. Broeg, S. Charnoz, C. Corral Van Damme, Sz Csizmadia, P. E. Cubillos, M. B. Davies, M. Deleuil, O. D.S. Demangeon, B. O. Demory, Doris Ehrenreich, A. Erikson, A. Fortier, M. Fridlund, M. Gillon, M. Güdel, Sergio Hoyer, K. G. Isaak, F. Kerschbaum, L. L. Kiss, J. Laskar, A. Lecavelier Des Etangs, D. Lorenzo-Oliveira, C. Lovis, D. Magrin, L. Marafatto, P. F.L. Maxted, J. Meléndez, C. Mordasini, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, D. Piazza, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, G. Scandariato, D. Ségransan, A. E. Simon, A. M.S. Smith, M. Steller, Gy M. Szabó, N. Thomas, S. Udry, B. Ulmer, V. Van Grootel, J. Venturini, N. A. Walton
Abstract: Context. TOI-1055 is a Sun-like star known to host a transiting Neptune-sized planet on a 17.5-day orbit (TOI-1055 b). Radial velocity (RV) analyses carried out by two independent groups using nearly the same set of HARPS spectra have provided measurements of planetary masses that differ by ∼2σ. Aims. Our aim in this work is to solve the inconsistency in the published planetary masses by significantly extending the set of HARPS RV measurements and employing a new analysis tool that is able to account and correct for stellar activity. Our further aim was to improve the precision on measurements of the planetary radius by observing two transits of the planet with the CHEOPS space telescope. Methods. We fit a skew normal function to each cross correlation function extracted from the HARPS spectra to obtain RV measurements and hyperparameters to be used for the detrending. We evaluated the correlation changes of the hyperparameters along the RV time series using the breakpoint technique. We performed a joint photometric and RV analysis using a Markov chain Monte Carlo scheme to simultaneously detrend the light curves and the RV time series. Results. We firmly detected the Keplerian signal of TOI-1055 b, deriving a planetary mass of Mb = 20.4-2.5+2.6 MO (∼12%). This value is in agreement with one of the two estimates in the literature, but it is significantly more precise. Thanks to the TESS transit light curves combined with exquisite CHEOPS photometry, we also derived a planetary radius of Rb = 3.490-0.064+0.070 RO (∼1.9%). Our mass and radius measurements imply a mean density of ρb = 2.65-0.35+0.37 g cm-3 (∼14%). We further inferred the planetary structure and found that TOI-1055 b is very likely to host a substantial gas envelope with a mass of 0.41-0.20+0.34 MO and a thickness of 1.05-0.29+0.30 RO. Conclusions. Our RV extraction combined with the breakpoint technique has played a key role in the optimal removal of stellar activity from the HARPS time series, enabling us to solve the tension in the planetary mass values published so far for TOI-1055 b.
Organisation(s): Department of Astrophysics
External organisation(s): Österreichische Akademie der Wissenschaften (ÖAW), Università degli Studi di Torino, Universität Bern, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Université de Genève, Stockholm University, Universidade do Porto, University of St. Andrews, University of Oxford, Université de Liège, Thüringer Landessternwarte Tautenburg, University College London, Massachusetts Institute of Technology, European Southern Observatory (Germany), Institute of Astrophysics of the Canary Islands, University of La Laguna, Universitat Autònoma de Barcelona , Spanish National Research Council (CSIC), Institute of Space Studies of Catalonia (IEEC), Admatis Ltd., European Space Astronomy Centre (ESA), Flatiron Institute, University of Grenoble Alpes, Osservatorio Astronomico, Université de Paris, Science and Operations Department - Science Division (SCI-SC), INAF-Osservatorio Astrofisico di Torino, Lund University, Aix-Marseille Université, Leiden University, Chalmers University of Technology, Eötvös Loránd Research Network, Eötvös Loránd University Budapest, Université de recherche Paris Sciences et Lettres, Université Paris VI - Pierre-et-Marie-Curie, Laboratório Nacional de Astrofísica, Keele University, INAF-Osservatorio Astrofisico di Catania, University of Padova, University of Warwick, Eidgenössische Technische Hochschule Zürich, University of Cambridge, Technische Universität Berlin, Freie Universität Berlin (FU), University of São Paulo, Instituto Oceanográfico
Journal: Astronomy and Astrophysics
Volume: 671
No. of pages: 13
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202245607
Publication date: 03-2023
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/54ec900a-f8ff-498b-98ce-d0348dbc53a2

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