Issue |
A&A
Volume 475, Number 3, December I 2007
|
|
---|---|---|
Page(s) | 1019 - 1025 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20078024 | |
Published online | 02 October 2007 |
Does convective core overshooting depend on stellar mass?*
Tests using double-lined eclipsing binaries
Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain e-mail: claret@iaa.es
Received:
6
June
2007
Accepted:
18
September
2007
Aims.We have selected 13 double-line eclipsing binary systems
(DLEBS), strategically positioned in the HR diagram, to infer
the mass dependence of the core overshooting parameter .
Methods. In order to compare the data from these DLEBS with the theoretical predictions
we computed four grids of evolutionary stellar models with variable amounts of core
overshooting (, 0.2, 0.4, and 0.6) in addition
to those previously computed. In some particular cases specific models were
computed for the precise observed masses. This procedure avoids interpolations and
extrapolations, and only considers chemical compositions within the limits of the
usual primordial helium abundance and enrichment law.
Results.We used the ratio TR instead of the effective
temperatures themselves as we consider it a much better constrained
parameter. This is because it is directly derived from the analysis of light curves
and is independent of calibrations, distances, and model
atmospheres. In contrast to previous studies on the subject, we have found
that standard models or models with moderate core overshooting
(
) are able to match the absolute dimensions of key
DLEBS such as V380 Cyg or V453 Cyg.
The resulting
diagram indicates that
the dependence of
on mass is more uncertain and less pronounced that
previously established. This result is also consistent with the analysis of colour-magnitude
diagrams for clusters and with previous comparisons of stellar models with larger samples of DLEBS.
Key words: stars: binaries: eclipsing / stars: evolution / stars: interiors
© ESO, 2007
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