| Autor: |
Ge, Z. S., Bi, S. L., Li, T. D., Liu, K., Tian, Z. J., Yang, W. M., Liu, Z. E. |
| Předmět: |
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| Zdroj: |
Monthly Notices of the Royal Astronomical Society; 2/11/2015, Vol. 447 Issue 1, p680-690, 11p |
| Abstrakt: |
We intend to use stellar models with and without α-enhancement, as well as asteroseismic analysis, to study two α-enhanced stars, KIC 7976303 and KIC 8694723. For the α-enhanced models, we adopt [α/Fe] = 0.2 and 0.4. For the evolved subgiant KIC 7976303 with mixed modes, the α-enhanced models fit the observations better than the models without α-enhancement, and point to a star with M = 1.20 ± 0.02M⊙, t = 4.88 ± 0.08Gyr, R = 2.04 ± 0.01 R⊙ and L = 5.07 ± 0.05 L⊙. For the post turn-off star KIC 8694723, we find that the models fit the observations well in all three cases ([α/Fe] = 0.0, 0.2 and 0.4). According to the observed metal abundances, only α-enhanced models are used to estimate the stellar parameters, which are M = 1.13 ± 0.06M⊙, t = 5.47 ± 0.43Gyr, R = 1.55 ± 0.13 R⊙ and L = 3.18 ± 0.26 L⊙. Our α-enhanced models indicate that KIC 7976303 has a larger mass and younger age than in previous works based on standard models. Furthermore, the differences of estimated mass and age between the three cases are~0.1M⊙ and ~0.5-1.3Gyr. These results suggest that we include α-enhancement in the modelling of α-enhanced stars, such as members of globular clusters and metal-poor stars in the disc and in the halo. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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