Binarity as a tool for determining thephysical properties and evolutionary aspectsof A-stars

The A-Star Puzzle IAUS 224, Poprad, Slovakya, 08 Temmuz 2004, cilt.224, ss.81-88

Double-lined-eclipsing binaries are the essential systems for the measurement of

stellar masses and radii. About 50-60 systems have components (mostly A-stars) for which

these values are known with an uncertainty less than 1-2%. Therefore, these systems are very

suitable to improve our understanding of stellar structure and evolution. In this paper, special

attention is given to the assessment of the role of internal rotation of the early-type stars in

selected double-lined binaries (i.e., EK Cep, PV Cas, and θ

2 Tau): it is shown that adoption of

rapidly rotating cores for such stars permits the models to be in very good agreement with the

observational results including the apsidal advance rates.