Cool Stars 14 - Submitted Abstract # 76
This version created on 05 October 2006
Models of alpha Centauri A and B with and without seismic constraints:
the time dependence of the mixing-length parameter
Mutlu Yildiz, Ege University
The alpha Cen binary system is one of the well known stellar systems
with very accurate observational constraints to structure of its
component stars. In addition to the classical non-seismic
constraints, we have also seismic constraints for the interior models
of alpha Cen A and B. While we obtain 8.9 Gyrs for the age of the
system for non-seismic constraints, the seismic constraints imply that
it is about 5.6-5.9 Gyrs. The alpha Cen binary system with its solar
type components is also very suitable for testing the stellar mass
dependence of the mixing-length parameter for convection derived from
the binaries of Hyades. We can interpret this mass dependence as it
is valid near the zero-age-main-sequence and we will be observing how
it will be as stars evolve. The values of the mixing-length parameter
for alpha Cen A and B are 2.10 and 1.90 for the non-seismic
constraints. If we employ the seismic constraints together with the
non-seismic constraints (except the luminosity of alpha Cen B), we
obtain 1.64 and 1.91 for alpha Cen A and B, respectively. By taking
care of these two different aspects for the mixing-length parameter,
we derive two expressions for its time dependence which are also
compatible with the mass dependence of the mixing-length parameter
derived from the Hyades stars.
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