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Astron. Astrophys. 327, 207-214

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Biparametric calibrations of stellar mass, radius
and surface gravity using uvby-HFORMULA photometry

I. Ribas1, C. Jordi1, J. Torra1, and A. Giménez2

1Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Avda. Diagonal 647, E-08028 Barcelona, Spain
2INTA-LAEFF, Apartado 50727, E-28080 Madrid, Spain

Received 14 April 1997 / Accepted 18 June 1997


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 (FORMULA 1-2%) determinations of mass and radius and with available Strömgren-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 0.08-0.10 dex in surface gravity for stars in the main sequence with Teff in the range between 7000 K and 20000 K. Precisions are thus considerably better than those obtained through single-parameter calibrations (using spectral type, Teff or one colour index), and comparable to those derived through model atmospheres and stellar evolutionary models, of much higher complexity.

Key words: stars: fundamental parameters - stars: binaries: eclipsing - stars: early-type - stars: late-type - stars: general

Send offprint requests to: I. Ribas

© European Southern Observatory (ESO) 1997

Online publication: October 1, 1997
Last change: April 8, 1998