The EBLM project X. Benchmark masses, radii and temperatures for two fully convective M-dwarfs using K2

Alison Duck*, David V. Martin, Sam Gill, Tayt Armitage, Romy Rodríguez Martínez, Pierre F. L. Maxted, Daniel Sebastian, Ritika Sethi, Matthew I. Swayne, Andrew Collier Cameron, Georgina Dransfield, B. Scott Gaudi, Michael Gillon, Coel Hellier, Vedad Kunovac, Christophe Lovis, James McCormac, Francesco A. Pepe, Don Pollacco, Lalitha SairamAlexandre Santerne, Damien Ségransan, Matthew R. Standing, John Southworth, Amaury H. M. J. Triaud, Stephane Udry

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

M-dwarfs are the most abundant stars in the galaxy and popular targets for exoplanet searches. However, their intrinsic faintness and complex spectra inhibit precise characterisation. We only know of dozens of M-dwarfs with fundamental parameters of mass, radius and effective temperature characterised to better than a few per cent. Eclipsing binaries remain the most robust means of stellar characterisation. Here we present two targets from the Eclipsing Binary Low Mass (EBLM) survey that were observed with K2: EBLM J0055-00 and EBLM J2217-04. Combined with HARPS and CORALIE spectroscopy, we measure M-dwarf masses with precisions better than 5%, radii better than 3% and effective temperatures on order 1%. However, our fits require invoking a model to derive parameters for the primary star. By investigating three popular models, we determine that the model uncertainty is of similar magnitude to the statistical uncertainty in the model fits. Therefore, whilst these can be considered benchmark M-dwarfs, we caution the community to consider model uncertainty when pushing the limits of precise stellar characterisation.
Original languageEnglish
Article numberstad452
JournalMonthly Notices of the Royal Astronomical Society
VolumeAdvance Article
DOIs
Publication statusAccepted/In press - 24 Feb 2023

Keywords

  • Stars: binaries-eclipsing
  • Low-mass
  • Fundamental parameters
  • Techniques: photometric
  • Spectroscopic

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