CAOSP abstracts, Volume: 55, No.: 3, year: 2025

Author(s): Sebastian, D.; Triaud, A.H.M.J.; Maxted, P.F.L.; Brogi, M.
Journal: Contributions of the Astronomical Observatory Skalnaté Pleso, vol. 55, no. 3, p. 412-420.
Date: 04/2025
Title: Accurate dynamical masses from binaries with extreme brightness ratios
Keyword(s): binaries: spectroscopic, stars: fundamental parameters, planets and satellites: atmospheres, stars: low-mass, binaries: eclipsing, techniques: spectroscopic
Pages: 412 -- 420
DOI: https://doi.org/10.31577/caosp.2025.55.3.412
NASA ADS Abstract Service: 2025CoSka..55c.412S
Citation:
License: This work is licensed under a Creative Commons Attribution 4.0 International License

Abstract: High-resolution cross-correlation techniques are a powerful tool to explore exoplanet atmospheres. We introduce their application to binary stars from the EBLM project. In particular, we focus on eclipsing, high-contrast binaries consisting of a solar-type star and a low mass M-dwarf companion. These binary systems have typical brightness ratios ∼ 0.1% at optical wavelengths and appear as single-lined binaries in optical high-resolution spectra. Since the spectral features of low-mass stars are well known, we can recover the signal of the M-dwarf companion from what otherwise appears as noise, and accurately measure the masses of both stars, turning the system into a double-lined binary. We show that this application is a powerful new tool to not only derive accurate and precise dynamical masses for fully convective stars, but also to extract phase-dependent information. We will furthermore discuss the application to high-resolution infrared spectroscopy to characterise stars at the very bottom of the main-sequence.