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arXiv · 2103.02077

The surface brightness - colour relations based on eclipsing binary stars and calibrated with Gaia EDR3

Abstract

The surface brightness -- colour relation (SBCR) is a basic tool in establishing precise and accurate distances within the Local Group. Detached eclipsing binary stars with accurately determined radii and trigonometric parallaxes allow for a calibration of the SBCRs with unprecedented accuracy. We analysed four nearby eclipsing binary stars containing late F-type main sequence components: AL Ari, AL Dor, FM Leo and BN Scl. We determined very precise spectroscopic orbits and combined them with high precision ground- and space-based photometry. We derived the astrophysical parameters of their components with mean errors of 0.1% for mass and 0.4% for radius. We combined those four systems with another 24 nearby eclipsing binaries with accurately known radii from the literature for which $Gaia$ EDR3 parallaxes are available, in order to derive the SBCRs. The resulting SBCRs cover stellar spectral types from B9 V to G7 V. For calibrations we used Johnson optical $B$ and $V$, $Gaia$ $G_{\rm BP}$ and $G$ and 2MASS $JHK$ bands. The most precise relations are calibrated using the infrared $K$ band and allow to predict angular diameters of A-, F-, and G-type dwarf and subgiant stars with a precision of 1%.

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D. Graczyk, G. Pietrzyński, C. Gałan, W. Gieren, A. Tkachenko, R. I. Anderson, A. Gallenne, M. Górski, G. Hajdu, M. Kałuszyński, P. Karczmarek, P. Kervella, P. F. L. Maxted, N. Nardetto, W. Narloch, K. Pavlovski, B. Pilecki, W. Pych, J. Southworth, J. Storm, K. Suchomska, M. Taormina, S. Villanova, P. Wielgórski, B. Zgirski, P. Konorski. 2021-03-02. The surface brightness - colour relations based on eclipsing binary stars and calibrated with Gaia EDR3. https://doi.org/10.1051/0004-6361/202140571

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