论文标题
RR Lyrae星星的星星学具有非radial模式
Asteroseismology of RR Lyrae stars with non-radial modes
论文作者
论文摘要
在第一个过时的RR Lyre恒星的频谱中观察到的其他信号，该恒星与第一个泛音的周期相比形成了一个周期比，这是RRC和RRD恒星的常见现象，以及首先反过来的经典cephe虫。最近提出的模型将这些信号解释为在RR Lyrae恒星的情况下，在经典头孢虫的情况下，在RR Lyrae星和7、8或9的情况下，这些信号是8或9的谐波。我们至少选择了在径向和非radial模式中脉动的三型RR Lyrae恒星进行星际震归于模型。我们假设识别该模型所预测的非radial模式。我们使用包络脉动代码计算了RR Lyrae恒星模型的密集网格。通过匹配第一个泛音周期和周期比，我们获得了所选三模式恒星样品的物理参数。这是将RR Lyrae星形恒星用非radial模式建模的第一次尝试。我们将我们的结果与恒星进化理论的预测进行了比较，这导致质量差异对于长期恒星更为明显：脉动质量似乎高于进化质量。我们比较了模型样品的RRC恒星的金属度估计值，并在太阳邻域中的RRC恒星样品进行光谱确定的金属度进行了比较：这两个分布都是一致的。
The additional signals observed in the frequency spectra of the first-overtone RR Lyrae stars, that form a period ratio around 0.61 with the period of the first overtone, are a common phenomenon for RRc and RRd stars, as well as for first-overtone classical Cepheids. The recently proposed model explains these signals as harmonics of non-radial modes of degrees 8 or 9 in the case of RR Lyrae stars and 7, 8, or 9 in the case of classical Cepheids. We selected at least triple-mode RR Lyrae stars pulsating in radial and non-radial modes for asteroseismic modeling. We assume the identification of the non-radial modes as predicted by the model. We calculated a dense grid of models for RR Lyrae stars using envelope pulsation code. By matching first overtone period and period ratios we obtained physical parameters for the selected sample of triple-mode stars. It is the very first attempt of modeling RR Lyrae stars with non-radial modes. We compared our results with predictions of stellar evolution theory, which resulted in a mass discrepancy more noticeable for long-period stars: pulsation masses seem higher than evolutionary masses. We compared metallicity estimates for RRc stars from modeled sample with metallicities determined spectroscopically for a sample of RRc stars in the solar neighbourhood: both distributions are consistent.
