1997A&A...327..207R

The aim of this study is to construct biparametric calibrations to estimate masses, radii and surface gravities for main-sequence stars using a photometric index related to effective temperature and another related to evolution. For this purpose, we used a sample of detached double-lined eclipsing binaries with accurate (≃1-2%) determinations of mass and radius and with available Stroemgren-Crawford photometry for the individual components of the binary system. The accuracies obtained, for the predicted dimensions when applied to single stars, are about 5-8% in mass, 10-15% in radius and 0.08-0.10dex in surface gravity for stars in the main sequence with T_eff in the range between 7000K and 20000K. Precisions are thus considerably better than those obtained through single-parameter calibrations (using spectral type, T_eff or one colour index), and comparable to those derived through model atmospheres and stellar evolutionary models, of much higher complexity.