论文标题
BA和CEMP-S星的光谱研究：AGB祖细胞的质量分布
Spectroscopic study of Ba and CEMP-s stars: Mass distribution of AGB progenitors
论文作者
论文摘要
我们已经对七个金属贫困星（BD+75 348，BD+09 3019，HD238020，HE0319-0215，HE0507-1653，HE0930-0018，HE0930-0018，HE1023-1504）进行了详细的高分辨率光谱分析（BD+75 348，BD+09 3019，HE0319-0215和麦片速度速度（$ξ$）。发现金属范围为-2.57 $ <$ [fe/h] $ <$ - 0.42。估计了17个光元素和12个重元素的元素丰度。我们将BD+75 348和BD+09 3019分类为强BA星，HD238020作为温和的BA星，其余四个物体为CEMP-S星。我们已经估计了来自Hertzsprung-Russel（HR）图的恒星质量，并估计了文献中205个BA恒星的数据，估计了BA恒星的质量分布。我们还凭借基于参数模型的分析，使用果味模型估计了程序明星的伴随AGB的初始质量以及文献中159 ba和36个CEMP-S星的伴侣AGB的质量。温和BA星的主要质量分布在3.7 m $ _ {\ odot} $中达到峰值，而对于强BA星，峰值出现在2.5 m $ _ {\ odot} $。因此，我们建议祖细胞AGB的初始质量主要控制轻度和强BA星的形成。但是，在1.3-4.0 m $ _ {\ odot} $范围内的明显重叠，在两个BA星的子类的祖细胞群体之间注意到，可能表明其他因素（例如金属性和轨道时期）也可能有很大的贡献。发现CEMP-S星的祖细胞AGB的质量分布在2.03 m $ _ {\ odot} $中达到峰值。
We have performed detailed high-resolution spectroscopic analysis on seven metal-poor stars (BD+75 348, BD+09 3019, HD238020, HE0319-0215, HE0507-1653, HE0930-0018, HE1023-1504) and derived their atmospheric parameters T$_{eff}$, log$g$, [Fe/H], and mictroturbulent velocity ($ξ$). The metallicity range is found to be -2.57$<$[Fe/H]$<$-0.42. The elemental abundances of 17 light elements and 12 heavy elements are estimated. We have classified BD+75 348 and BD+09 3019 as strong Ba stars, HD238020 as a mild Ba star, and the remaining four objects as CEMP-s stars. We have estimated the masses of the stars from Hertzsprung-Russel (HR) diagram, and, compiling the data of 205 Ba stars from literature, estimated the mass distribution of Ba stars. We have also estimated the initial masses of the companion AGBs of the program stars as well as the masses of the companion AGBs of 159 Ba and 36 CEMP-s stars from literature, with the help of a parametric-model-based analysis using FRUITY models. While the primary mass distribution of mild Ba stars peaks at 3.7 M$_{\odot}$, for the strong Ba stars the peak appears at 2.5 M$_{\odot}$. We, therefore, propose that the initial masses of the progenitor AGBs dominantly control the formation of mild and strong Ba stars. However, a clear overlap, in the range 1.3-4.0 M$_{\odot}$, noticed between the progenitor masses of both the subclasses of Ba stars, may indicate that other factors, such as metallicities and the orbital periods, may also have significant contributions. The progenitor AGBs' mass distribution of CEMP-s stars is found to peak at 2.03 M$_{\odot}$.
