Analysis of $\alpha$ Centauri AB including seismic constraints
Analysis of $\alpha$ Centauri AB including seismic constraints
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DOI：
10.1051/0004-6361:20034203
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发表时间：
2004-01
影响因子：
6.5
通讯作者：
P. Eggenberger;C. Charbonnel;S. Talon;G. Meynet;A. Maeder;Fabien Carrier;G. Bourban
中科院分区：
文献类型：
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作者：
P. Eggenberger;C. Charbonnel;S. Talon;G. Meynet;A. Maeder;Fabien Carrier;G. Bourban
基于Carrier&Bourban([CITE])的αCen B新地震学数据，利用包含原子扩散的日内瓦演化程序计算了αCen A和B的详细模型。考虑到目前αCEN系统可用的众多观测约束，我们找到了一个与天体测量、光度学、光谱和星震数据很好地吻合的恒星模型。αCeN系统的总体参数现在被严格地限制为年龄$t=6.52\pm 0.30$Gyr，初始氦质量分数$Y{\mathm{i}}=0.275\pm 0.010$和初始金属丰度$(Z/X){\mathm{i}}=0.0434\pm 0.0020$。由于这些众多的观测限制，我们证实了B分量的混合长度参数α大于A分量的混合长度参数，这一点已经由许多作者提出(Noels等人)。[Cite]；Fernandes&Neuforge[Cite]；Guenther&Demarque[Cite])：$\pha_{\mathm{B}}$比$\pha_{\mathm{A}}$($\pha_{\mathm{A}}=1.83\pm 0.10$和$\pha_{\mathm{B}}=1.97\pm 0.10$)大约8%。此外，我们还表明，星震测量能够以非常高的精度(误差小于0.3%)确定两颗恒星的半径。从地震学数据推导出的半径与Kervella等人的新干涉结果是一致的。([引用])，即使它们略大于干涉半径(差异小于1%)。
Detailed models of α Cen A and B based on new seismological data for α Cen B by Carrier & Bourban ([CITE]) have been computed using the Geneva evolution code including atomic diffusion. Taking into account the numerous observational constraints now available for the α Cen system, we find a stellar model which is in good agreement with the astrometric, photometric, spectroscopic and asteroseismic data. The global parameters of the α Cen system are now firmly constrained to an age of $t=6.52 \pm 0.30$ Gyr, an initial helium mass fraction $Y_{\mathrm{i}}=0.275 \pm 0.010$ and an initial metallicity $(Z/X)_{\mathrm{i}}=0.0434 \pm 0.0020$. Thanks to these numerous observational constraints, we confirm that the mixing-length parameter α of the B component is larger than the one of the A component, as already suggested by many authors (Noels et al. [CITE]; Fernandes & Neuforge [CITE]; Guenther & Demarque [CITE]): $\alpha_{\mathrm{B}}$ is about 8% larger than $\alpha_{\mathrm{A}}$ ($\alpha_{\mathrm{A}}=1.83 \pm 0.10$ and $\alpha_{\mathrm{B}}=1.97 \pm 0.10$). Moreover, we show that asteroseismic measurements enable to determine the radii of both stars with a very high precision (errors smaller than 0.3%). The radii deduced from seismological data are compatible with the new interferometric results of Kervella et al. ([CITE]) even if they are slightly larger than the interferometric radii (differences smaller than 1%).