The EBLM project - VIII. First results for M-dwarf mass, radius, and effective temperature measurements using CHEOPS light curves

Author(s)
M. Swayne, P. F. L. Maxted, A. H. M. J. Triaud, S. G. Sousa, C. Broeg, H-G Floren, P. Guterman, A. E. Simon, Boisse, A. Bonfanti, D. Martin, A. Santerne, S. Salmon, M. R. Standing, V. Van Grootel, T. G. Wilson, Y. Alibert, R. Alonso, G. Anglada Escude, J. Asquier, T. Barczy, D. Barrado, S. C. C. Barros, M. Battley, W. Baumjohann, M. Beck, T. Beck, A. Bekkelien, W. Benz, N. Billot, X. Bonfils, A. Brandeker, M-D Busch, J. Cabrera, S. Charnoz, A. Collier Cameron, Sz Csizmadia, M. B. Davies, M. Deleuil, A. Deline, L. Delrez, O. D. S. Demangeon, B-O Demory, G. Dransfield, D. Ehrenreich, A. Erikson, A. Fortier, L. Fossati, M. Fridlund, D. Futyan, D. Gandolfi, M. Gillon, M. Güdel, G. Hebrard, N. Heidari, C. Hellier, K. Heng, M. Hobson, S. Hoyer, K. G. Isaak, L. Kiss, V. Kunovac Hodzic, S. Lalitha, J. Laskar, A. Lecavelier des Etangs, M. Lendl, C. Lovis, D. Magrin, L. Marafatto, J. McCormac, N. Miller, Valerio Nascimbeni, G. Olofsson, R. Ottensamer, M Pagano, E. Palle, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, Ignasi Ribas, N. C. Santos, G. Scandariato, D. Segransan, A. M. S. Smith, M. Steinberger, M. Steller, Gy M. Szabo, N. Thomas, S. Udry, F Walter, N. A. Walton, E. Willett
Abstract

The accuracy of theoretical mass, radius, and effective temperature values for M-dwarf stars is an active topic of debate. Differences between observed and theoretical values have raised the possibility that current theoretical stellar structure and evolution models are inaccurate towards the low-mass end of the main sequence. To explore this issue, we use the CHEOPS satellite to obtain high-precision light curves of eclipsing binaries with low-mass stellar companions. We use these light curves combined with the spectroscopic orbit for the solar-type companion to measure the mass, radius, and effective temperature of the M-dwarf star. Here, we present the analysis of three eclipsing binaries. We use the pycheops data analysis software to fit the observed transit and eclipse events of each system. Two of our systems were also observed by the TESS satellite-we similarly analyse these light curves for comparison. We find consistent results between CHEOPS and TESS, presenting three stellar radii and two stellar effective temperature values of low-mass stellar objects. These initial results from our on-going observing programme with CHEOPS show that we can expect to have ∼24 new mass, radius, and effective temperature measurements for very low-mass stars within the next few years.

Organisation(s)
Department of Astrophysics
External organisation(s)
Keele University, University of Birmingham, Universidade do Porto, Universität Bern, Stockholm University, Aix-Marseille Université, National Institute for Earth Sciences & Astronomy (INSU-CNRS), Österreichische Akademie der Wissenschaften (ÖAW), Ohio State University, Université de Genève, Université de Liège, University of St. Andrews, Institute of Astrophysics of the Canary Islands, University of La Laguna, Spanish National Research Council (CSIC), Universitat Autònoma de Barcelona , Science and Operations Department - Science Division (SCI-SC), Admatis Ltd., University of Warwick, University of Grenoble Alpes, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Université de Paris, Lund University, Leiden University, Chalmers University of Technology, University of Turin, Université Paris IV - Paris-Sorbonne, Shahid Beheshti University, Université Nice-Sophia-Antipolis, Pontificia Universidad Católica de Chile, Hungarian Academy of Sciences, Eötvös Loránd University Budapest, The University of Sydney, Osservatorio Astronomico, INAF-Osservatorio Astrofisico di Catania, University of Padova, University of Cambridge, Technische Universität Berlin, Freie Universität Berlin (FU)
Journal
Monthly Notices of the Royal Astronomical Society
Volume
506
Pages
306-322
No. of pages
17
ISSN
0035-8711
DOI
https://doi.org/10.1093/mnras/stab1687
Publication date
09-2021
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/101e049c-d8e9-42e8-8607-6e93865f12f4