engleski

Abundances from disentangled spectra: challenge for advanced evolutionary models

The stellar evolutionary models predict, besides the time-evolution of global parameters like effective temeprature, luminosity, etc., also changes in the chemical composition. This opportunity to test theoretical predictions in the case of close binaries was not exploited widely due to a number of technical difficulties. Concentrating on early-type stars I will first review previous research in this direction and controversies which arose, as e.g. mass discrepancy, helium overabundances already on the main-sequence, etc. Recent techniques to derive the intrinsic component spectra from observed composite binary spectra have opened a new window for detailed spectrosocpic diagnostics from binaries. The availability of more precise fundamental stellar parameters than for non-binary stars makes the comparison with evolutionary models more direct and precise. I will illustrate the possibilities with the first results of an on-going observational project, discussing the case study of the massive, detached, eclipsing, double-lined spectroscopic binary V578 Monocerotis in the very young stellar cluster NGC 2244, which is embedded in the Rosette Nebula.

binary stars; chemical abundances; spectroscopy

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