Testing stellar evolution models with the retired A star HD 185351
Testing stellar evolution models with the retired A star HD 185351
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DOI：
10.1093/mnras/stw2559
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发表时间：
2016-10
影响因子：
4.8
通讯作者：
Jakob G. Hjørringgaard;V. S. Aguirre;T. White;D. Huber;B. Pope;L. Casagrande;A. B. Justesen;J. Christensen-Dalsgaard
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作者：
Jakob G. Hjørringgaard;V. S. Aguirre;T. White;D. Huber;B. Pope;L. Casagrande;A. B. Justesen;J. Christensen-Dalsgaard
Johnson 等人对退役 A 星 HD 185351 的物理参数进行了详细分析。 (2014) 使用干涉测量、光谱学和星震学。所有独立方法的结果均与质量超过 $1.5\mathrm{M}_{\odot}$ 的 HD 185351 一致。然而，该研究还表明，并非所有观测约束都能在恒星演化模型中得到调和，导致质量估计范围在 $\sim 1.6-1.9\mathrm{M}_{\odot}$ 之间，并对星震学确定的恒星特性的准确性产生怀疑。在这里，我们解决了这一差异，并构建了一个与 HD 185351 物理参数的所有观测约束一致的理论模型。检查了不同输入物理场的影响，并考虑了观测到的 g 模式周期间隔的附加约束。人们发现这个量对主序列期间来自对流核心的额外混合很敏感，并且可以用来校准使用低光度红巨星的超调效率。金属量 $\left[\mathrm{Fe/H}\right]=0.16$dex、混合长度参数 $\alpha_{\mathrm{MLT}}=2.00$ 和对流超调效率参数 $f=0.030$ 的理论模型与 $M\simeq1.60\mathrm{M}_{\odot}$ 恒星质量的所有观测约束完全一致。
The physical parameters of the retired A star HD 185351 were analysed in great detail by Johnson et al. (2014) using interferometry, spectroscopy and asteroseismology. Results from all independent methods are consistent with HD 185351 having a mass in excess of $1.5\mathrm{M}_{\odot}$. However, the study also showed that not all observational constraints could be reconciled in stellar evolutionary models, leading to mass estimates ranging from $\sim 1.6-1.9\mathrm{M}_{\odot}$ and casting doubts on the accuracy of stellar properties determined from asteroseismology. Here we solve this discrepancy and construct a theoretical model in agreement with all observational constraints on the physical parameters of HD 185351. The effects of varying input physics are examined as well as considering the additional constraint of the observed g-mode period spacing. This quantity is found to be sensitive to the inclusion of additional mixing from the convective core during the main sequence, and can be used to calibrate the overshooting efficiency using low-luminosity red giant stars. A theoretical model with metallicity $\left[\mathrm{Fe/H}\right]=0.16$dex, mixing-length parameter $\alpha_{\mathrm{MLT}}=2.00$, and convective overshooting efficiency parameter $f=0.030$ is found to be in complete agreement with all observational constraints for a stellar mass of $M\simeq1.60\mathrm{M}_{\odot}$.