The EBLM Project– XI. Mass, radius, and effective temperature measurements for 23 M-dwarf companions to solar-type stars observed with CHEOPS

Author(s): M. I. Swayne, P. F.L. Maxted, A. H.M.J. Triaud, S. G. Sousa, A. Deline, D. Ehrenreich, S. Hoyer, G. Olofsson, I. Boisse, A. Duck, S. Gill, D. Martin, J. McCormac, C. M. Persson, A. Santerne, D. Sebastian, M. R. Standing, L. Acuña, Y. Alibert, R. Alonso, G. Anglada, T. Bárczy, D. Barrado Navascues, S. C.C. Barros, W. Baumjohann, T. A. Baycroft, M. Beck, T. Beck, W. Benz, N. Billot, X. Bonfils, L. Borsato, V. Bourrier, A. Brandeker, C. Broeg, A. Carmona, S. Charnoz, A. Collier Cameron, P. Cortés-Zuleta, Sz Csizmadia, P. E. Cubillos, M. B. Davies, M. Deleuil, X. Delfosse, L. Delrez, O. D.S. Demangeon, B. O. Demory, G. Dransfield, A. Erikson, A. Fortier, T. Forveille, L. Fossati, M. Fridlund, D. Gandolfi, M. Gillon, M. Güdel, M. N. Günther, N. Hara, G. Hébrard, N. Heidari, C. Hellier, Ch Helling, K. G. Isaak, F. Kerschbaum, F. Kiefer, L. L. Kiss, V. Kunovac, S. Lalitha, K. W.F. Lam, J. Laskar, A. Lecavelier des Etangs, M. Lendl, D. Magrin, L. Marafatto, E. Martioli, N. J. Miller, C. Mordasini, C. Moutou, V. Nascimbeni, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, D. Piazza, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, N. C. Santos, G. Scandariato, D. Ségransan, A. E. Simon, A. M.S. Smith, R. Southworth, M. Stalport, Gy M. Szabó, N. Thomas, S. Udry, B. Ulmer, V. Van Grootel, J. Venturini, N. A. Walton, E. Willett, T. G. Wilson
Abstract: Observations of low-mass stars have frequently shown a disagreement between observed stellar radii and radii predicted by theoretical stellar structure models. This ‘radius inflation’ problem could have an impact on both stellar and exoplanetary science. We present the final results of our observation programme with the CHaracterising ExOPlanet Satellite (CHEOPS) to obtain high-precision light curves of eclipsing binaries with low-mass stellar companions (EBLMs). Combined with the spectroscopic orbits of the solar-type companions, we can derive the masses, radii, and effective temperatures of 23 M-dwarf stars. We use the PYCHEOPS data analysis software to analyse their primary and secondary occultations. For all but one target, we also perform analyses with Transiting Exoplanet Survey Satellite (TESS) light curves for comparison. We have assessed the impact of starspot-induced variation on our derived parameters and account for this in our radius and effective temperature uncertainties using simulated light curves. We observe trends in inflation with both metallicity and orbital separation. We also observe a strong trend in the difference between theoretical and observational effective temperatures with metallicity. There is no such trend with orbital separation. These results are not consistent with the idea that the observed inflation in stellar radius combines with lower effective temperature to preserve the luminosity predicted by low-mass stellar models. Our EBLM systems provide high-quality and homogeneous measurements that can be used in further studies of radius inflation.
Organisation(s): Department of Astrophysics
External organisation(s): Keele University, University of Birmingham, Universidade do Porto, Université de Genève, Aix-Marseille Université, Stockholm University, Tufts University, University of Warwick, Chalmers University of Technology, Open University, Universität Bern, Institute of Astrophysics of the Canary Islands, University of La Laguna, Spanish National Research Council (CSIC), Institute of Space Studies of Catalonia (IEEC), Admatis Ltd., European Space Astronomy Centre (ESA), Österreichische Akademie der Wissenschaften (ÖAW), University of Grenoble Alpes, Osservatorio Astronomico, Université de Paris, University of St. Andrews, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), INAF-Osservatorio Astrofisico di Torino, Lund University, Université de Liège, Leiden University, University of Turin, Science and Operations Department - Science Division (SCI-SC), Université Paris VI - Pierre-et-Marie-Curie, Centre National De La Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur, Technische Universität Graz, Université de recherche Paris Sciences et Lettres, Eötvös Loránd Research Network, Eötvös Loránd University Budapest, Laboratório Nacional de Astrofísica, Polish Academy of Sciences, University of Toulouse, INAF-Osservatorio Astrofisico di Catania, University of Padova, Eidgenössische Technische Hochschule Zürich, University of Cambridge, Technische Universität Berlin, Freie Universität Berlin (FU), HUN-REN-ELTE Exoplanet Research Group
Journal: Monthly Notices of the Royal Astronomical Society
Volume: 528
Pages: 5703-5722
No. of pages: 20
ISSN: 0035-8711
DOI: https://doi.org/10.1093/mnras/stad3866
Publication date: 03-2024
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/7c358e8e-fa87-4cb1-ae94-4f02553118ba

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