Title: Exploring giant barium stars: $^{12}\rm{C}/^{13}\rm{C}$ ratio and elemental abundances of carbon, nitrogen, and oxygen Show Chinese title

Title: 探索巨型钡星：$^{12}\rm{C}/^{13}\rm{C}$比例和碳、氮和氧的元素丰度

Abstract: Barium (Ba) stars belong to binary systems that underwent mass transfer events. As a consequence, their envelopes were enriched with material synthesized in the interiors of their evolved companions via \textit{slow} neutron-capture nucleosynthesis, the $s$-process. As post-interacting binaries, Ba stars figure as powerful tracers of the $s$-process. In this study, we conduct a classical local thermodynamic equilibrium analysis for a sample of 180 Ba giant stars to find complementary insights for the $s$-process, in form of elemental abundances of carbon, nitrogen, and oxygen, as well as the $^{12}\rm{C}/^{13}\rm{C}$ ratio. We found carbon abundances systematically larger than those observed in normal giants, with [C/Fe] ratios ranging within from $-0.30$ to $+0.60$~dex. As expected, the [C/Fe] ratios increase for lower metallicity regimes and are strongly correlated with the average $s$-process abundances. Nitrogen abundances have a flat behavior around $\rm{[N/Fe]}\sim+0.50$~dex and are moderately correlated with sodium abundances. Except for HD~107541, the entire sample shows $\rm{C/O}<1$. We found $^{12}\rm{C}/^{13}\rm{C}<20$ for $\sim80\%$ of the sampled stars and $^{12}\rm{C}/^{13}\rm{C}>60$ for three objects. Show Chinese abstract

Abstract: 钡（Ba）星属于经历了质量转移事件的双星系统。 因此，它们的包层通过\textit{缓慢}中子捕获核合成，即$s$过程，被其演化的伴星内部合成的物质所富集。 作为相互作用后的双星系统， Ba 星作为$s$过程的强大示踪物。 在本研究中，我们对一个包含 180 颗 Ba 巨星的样本进行了经典的局部热力学平衡分析，以通过碳、氮和氧的元素丰度以及$^{12}\rm{C}/^{13}\rm{C}$比率，获得对$s$过程的补充见解。 我们发现碳丰度系统性地大于正常巨星光谱中的观测值，[C/Fe] 比率范围从$-0.30$到$+0.60$~dex。 如预期的那样，[C/Fe] 比例在较低金属丰度区域增加，并与平均$s$-过程丰度强烈相关。 氮丰度在$\rm{[N/Fe]}\sim+0.50$~dex 附近表现出平坦的行为，并与钠丰度中等相关。 除了 HD~107541 外，整个样本显示$\rm{C/O}<1$。 我们发现对于采样恒星的$\sim80\%$有$^{12}\rm{C}/^{13}\rm{C}<20$，对于三个天体有$^{12}\rm{C}/^{13}\rm{C}>60$。