Surface abundances of light elements for a large sample of early B-type stars - II. Basic parameters of 107 stars

Abstract

Effective temperatures Teff, surface gravities log g and interstellar extinctions Av are found for 107 B stars. Distances d of the stars, which are based on the derived Teff, log g and Av values, show good agreement with those obtained from the Hipparcos parallaxes. Comparing the Teff and log g values with evolutionary computations, we infer masses, radii, luminosities, ages and relative ages of the stars. Empirical relations between the Teff and log g parameters, on the one hand, and the photometric indices Q, [C1] and β, on the other hand, are constructed; these relations give a fast method for the Teff and log g estimation of early and medium B stars. Inclusion of the infrared J, H and K colours into the Teff, log g and Av determination shows that (i) the Teff and log g parameters are altered only slightly; (ii) the Av value is rather sensitive to these colours, so an accuracy better than 0.05 mag in the JHK data is necessary for precise Av evaluation.