engleski

An observational study of an early mixing in high-mass stars

New stellar evolution models which include the effects of rotationally induced mixing have considerably changed understanding of the evolution of high-mass stars, particularly during the early phases of core hydrogen burning (Heger & Langer 2000, Meynet & Maeder 2000). Rotation is now recognized as an important physical effect which substantially changes the lifetime, chemical yields and stellar evolution. Detailed analysies of eclipsing and spectroscopic binary stars provides accurate astrophysical quantities (mass, radius, local surface gravity, effective temperatures, and age) for both components. This makes photospheric abundance determination much more accurate than it is possible for single stars. An extended observational project is undertaken to study abundance changes in high-mass stars, and to calibrate these effects in terms of stellar mass, lifetime, and rotational velocity. Results obtained so far for about a dozen high-mass stars will be presented.

binary stars; stellar evolution

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