论文标题
需要修改$δ$ scuti星星学的恒星泥石学
A need to revise stellar opacities from asteroseismology of $δ$ Scuti stars
论文作者
论文摘要
我们构建了四个双模式径向$δ$Δ$ scuti星的地震模型，该星星采用了三个数据库的不良度：Opal，OP和Oplib。目的是找到符合观察到的两个径向模式的频率的模型，并具有与观察到的值一致的有效温度和光度。使用基于蒙特卡洛模拟的贝叶斯分析，我们得到只有蛋白石地震模型才能在HR图中观察到的误差框中捕获。使用OP和OPLIB数据计算的地震模型更凉爽且发光较少。通过在这些模拟中包括侧磁通变化（所谓的参数$ f $）的相对幅度，我们限制了信封中对流的效率，由混合长度参数$α_ {\ rm mlt} $描述。我们得到$α_ {\ rm Mlt} \ BP PEG，AE UMA和RV ARI（人口I星）和$α_ {\ rm Mlt} \ SX PHE（人口II星）的$α_ {\ rm Mlt} \约1.0 $。对于所有的恒星，对流核心的过度效力似乎效率低下。对于经典的头孢虫或RR Lyr恒星，也应该发生类似的不透明度效果，这些恒星被用作测量宇宙的标准蜡烛。
We construct seismic models of the four double-mode radial $δ$ Scuti stars adopting opacities from three databases: OPAL, OP and OPLIB. The aim is to find the models that fit the observed frequencies of the two radial modes and have the effective temperature and luminosity consistent with the observed values. Using the Bayesian analysis based on Monte Carlo simulations, we obtain that only the OPAL seismic models are caught within the observed error box in the HR diagram. Seismic models computed with the OP and OPLIB data are much cooler and less luminous. By including the relative amplitude of the bolometric flux variations (the so-called parameter $f$) into these simulations, we constrain the efficiency of convection in the envelopes, described by the mixing length parameter $α_{\rm MLT}$. We get $α_{\rm MLT}\approx 0.5$ for BP Peg, AE UMa and RV Ari (Population I stars) and $α_{\rm MLT}\approx 1.0$ for SX Phe (Population II star). For all the stars, overshooting from the convective core seems inefficient. A similar effect of opacity should occur also for classical Cepheids or RR Lyr stars that are used as standard candles to measure the universe.
