EVOLUTIONARY STATUS AND INTERNAL STRUCTURE OF μ CASSIOPEIAE

다국어 초록 (Multilingual Abstract)

We investigate physical properties of the nearby ($\sim$ 7.5 \pc) astrometric binary $\mu$ Cas in the context of standard evolutionary theory.
Based on the spectroscopically determined relative abundances ($\AlphaoverFe$ $\gtrsim +0.4 \,\dex$, $\FeoverH \sim -0.7 \,\dex$), all physical inputs such as opacities and equation of state are consistently generated.
By combining recent spectroscopic analyses with the astrometric observations from the \emph{HIPPARCOS} parallaxes and the \emph{CHARA} array, the evolutionary model grids have been constructed.
Through the statistical evaluation of the $\chi^2$-minimization among alternative models, we find a reliable evolutionary solution ($M_A$, $M_B$, $t_{age}$) = (0.74 \Msun, 0.19 \Msun, 11 \Gyr) which excellently satisfies observational constraints.
In particular, we find that the helium abundance of $\mu$ Cas is comparable with the primordial helium contents ($Y_p \sim 0.245$).
On the basis of the well-defined stellar parameters of the primary star, the internal structure and the $p$-mode frequencies have been estimated.
From our seismic computation, $\mu$ Cas is expected to have a first order spacing $\Delta\nu \sim 169 \,\muHz$.
The ultimate goal of this study is to describe physical processes inside a low-mass star through a complete modelling from the spectroscopic observation to the evolutionary computation.

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