The EBLM project - IX. Five fully convective M-dwarfs, precisely measured with CHEOPS and TESS light curves

Author(s)
D. Sebastian, M. I. Swayne, P. F.L. Maxted, A. H.M.J. Triaud, S. G. Sousa, G. Olofsson, M. Beck, N. Billot, S. Hoyer, S. Gill, N. Heidari, D. V. Martin, C. M. Persson, M. R. Standing, Y. Alibert, R. Alonso, G. Anglada, J. Asquier, T. Bárczy, D. Barrado, S. C.C. Barros, M. P. Battley, W. Baumjohann, T. Beck, W. Benz, M. Bergomi, I. Boisse, X. Bonfils, A. Brandeker, C. Broeg, J. Cabrera, S. Charnoz, A. Collier Cameron, S. Csizmadia, M. B. Davies, M. Deleuil, L. Delrez, O. D.S. Demangeon, B. O. Demory, G. Dransfield, D. Ehrenreich, A. Erikson, A. Fortier, L. Fossati, M. Fridlund, D. Gandolfi, M. Gillon, M. Güdel, J. Hasiba, G. Hébrard, K. Heng, K. G. Isaak, L. L. Kiss, E. Kopp, V. Kunovac, J. Laskar, A. Lecavelier Des Etangs, M. Lendl, C. Lovis, D. Magrin, J. McCormac, N. J. Miller, V. Nascimbeni, R. Ottensamer, I. Pagano, E. Pallé, F. A. Pepe, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, S. Lalitha, A. Santerne, N. C. Santos, G. Scandariato, D. Ségransan, A. E. Simon, A. M.S. Smith, M. Steller, G. M. Szabó, N. Thomas, S. Udry, V. Van Grootel, N. A. Walton
Abstract

Eclipsing binaries are important benchmark objects to test and calibrate stellar structure and evolution models. This is especially true for binaries with a fully convective M-dwarf component for which direct measurements of these stars' masses and radii are difficult using other techniques. Within the potential of M-dwarfs to be exoplanet host stars, the accuracy of theoretical predictions of their radius and effective temperature as a function of their mass is an active topic of discussion. Not only the parameters of transiting exoplanets but also the success of future atmospheric characterization relies on accurate theoretical predictions. We present the analysis of five eclipsing binaries with low-mass stellar companions out of a subsample of 23, for which we obtained ultra-high-precision light curves using the CHEOPS satellite. The observation of their primary and secondary eclipses are combined with spectroscopic measurements to precisely model the primary parameters and derive the M-dwarfs mass, radius, surface gravity, and effective temperature estimates using the PYCHEOPS data analysis software. Combining these results to the same set of parameters derived from TESS light curves, we find very good agreement (better than 1 per cent for radius and better than 0.2 per cent for surface gravity). We also analyse the importance of precise orbits from radial velocity measurements and find them to be crucial to derive M-dwarf radii in a regime below 5 per cent accuracy. These results add five valuable data points to the mass-radius diagram of fully convective M-dwarfs.

Organisation(s)
Department of Astrophysics
External organisation(s)
University of Birmingham, Keele University, Universidade do Porto, Stockholm University, Université de Genève, Aix-Marseille Université, University of Warwick, Ohio State University, Chalmers University of Technology, 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), Science and Operations Department - Science Division (SCI-SC), Admatis Ltd., European Space Astronomy Centre (ESA), Österreichische Akademie der Wissenschaften (ÖAW), Osservatorio Astronomico, University of Grenoble Alpes, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Université de Paris, University of St. Andrews, Lund University, Université de Liège, Leiden University, Università degli Studi di Torino, Université Paris VI - Pierre-et-Marie-Curie, Eötvös Loránd Research Network, Eötvös Loránd University Budapest, Lowell Observatory, Université de recherche Paris Sciences et Lettres, INAF-Osservatorio Astrofisico di Catania, University of Padova, Eidgenössische Technische Hochschule Zürich, University of Cambridge, Technische Universität Berlin, Freie Universität Berlin (FU)
Journal
Monthly Notices of the Royal Astronomical Society
Volume
519
Pages
3546-3563
No. of pages
18
ISSN
0035-8711
DOI
https://doi.org/10.1093/mnras/stac2565
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/ca6ce13d-9dfd-49f8-9180-e7b5d5856eaa