标题： 低质量吸积后双星先祖的建模 显示英文标题

标题： Modeling the progenitors of low-mass post-accretion binaries

摘要： 大约一半质量数 A > 90 的重元素的质量是通过慢中子俘获过程（s-过程）形成的，该过程发生在演化中的渐近巨星分支（AGB）星中，其质量约为 1-6 $\rm{M_{\odot}}$。 通过模拟从AGB星吸积物质到双星钡（Ba）、CH以及碳增强的金属贫乏（CEMP）-s星的过程，可以研究s-过程。 通过将观测得到的表面参数和s-过程元素的1D-LTE丰度模式与理论双星吸积模型进行比较，我们旨在理解吸积系统的形成。 我们探讨了吸积物质稀释的程度，并描述了对流混合对观测表面丰度的影响。 我们计算了一组新的低质量吸积后系统吸积模型，共计2700个。 最大似然性比较确定了Ba、CH和CEMP-s星观测样本的最佳拟合模型。 我们在所有吸积后双星样本的质量范围内（2-3 $\rm{M_{\odot}}$）发现了具有一致性的AGB供体质量。 我们发现弱Ba星的形成场景是一个AGB星转移了一定数量的质量（$\leq$0.5 $\rm{M_{\odot}}$），导致形成一颗约2.0-2.5 $\rm{M_{\odot}}$的恒星。 强Ba星的最佳拟合最终质量约为1.0-2.0 $\rm{M_{\odot}}$，且有显著的吸积质量 (0.5 $\geq$$\rm{M_{\odot}}$)。 CH和CEMP-s星显示出较低的最终质量（~1.0 $\rm{M_{\odot}}$）和少量的转移物质(~0.1 $\rm{M_{\odot}}$)。 我们发现，Ba星通常吸积比CEMP-s和CH星更多的物质。 我们也发现，强Ba星必须吸积超过0.50 $\rm{M_{\odot}}$的物质才能解释它们的丰度模式，在这个限制下，我们无法重现强Ba星的观测质量分布。 弱Ba星、CEMP-s和CH星的质量分布通过我们的模型得到了很好的再现。 显示英文摘要

摘要： About half of the mass of all heavy elements with mass number A > 90 is formed through the slow neutron capture process (s-process), occurring in evolved asymptotic giant branch (AGB) stars with masses ~1-6 $\rm{M_{\odot}}$. The s-process can be studied by modeling the accretion of material from AGB stars onto binary barium (Ba), CH, and carbon-enhanced metal-poor (CEMP)-s stars. Comparing observationally derived surface parameters and 1D-LTE abundance patterns of s-process elements to theoretical binary accretion models, we aim to understand the formation of post-accretion systems. We explore the extent of dilution of the accreted material and describe the impact of convective mixing on the observed surface abundances. We compute a new grid of 2700 accretion models for low-mass post-accretion systems. A maximum-likelihood comparison determines the best fit models for observational samples of Ba, CH, and CEMP-s stars. We find consistent AGB donor masses in the mass range of 2-3 $\rm{M_{\odot}}$ across our sample of post-accretion binaries. We find the formation scenario for weak Ba stars is an AGB star transferring a moderate amount of mass ($\leq$0.5 $\rm{M_{\odot}}$) resulting in a ~2.0-2.5 $\rm{M_{\odot}}$ star. The strong Ba stars are best fit with lower final masses ~1.0-2.0 $\rm{M_{\odot}}$, and significant accreted mass ($\geq$0.5 $\rm{M_{\odot}}$). The CH and CEMP-s stars display lower final masses (~1.0 $\rm{M_{\odot}}$) and small amounts of transferred material (~0.1 $\rm{M_{\odot}}$). We find that Ba stars generally accrete more material than CEMP-s and CH stars. We also find that strong Ba stars must accrete more than 0.50 $\rm{M_{\odot}}$ to explain their abundance patterns, and in this limit we are unable to reproduce the observed mass distribution of strong Ba stars. The mass distributions of the weak Ba stars, CEMP-s, and CH stars are well reproduced in our modeling.