论文标题
两个新的Li-Rich巨人的Lamost/HRS光谱分析
LAMOST/HRS Spectroscopic Analysis of Two New Li-rich Giants
论文作者
论文摘要
在新的高分辨率梯形光谱仪Lamost/HRS中观察到了两个Li-RiCH的候选者TYC 1338-1410-1和TYC 2825-596-1。基于高分辨率和高信号与噪声比率（SNR）光谱，我们得出了两个候选者的14个重要元素的恒星参数和丰度。恒星参数和锂丰度表明它们是含有液体的k型巨人，并且它们的（li）$ _ \ mathrm {nlte} $分别为1.77和2.91 dex。我们的分析表明，TYC 1338-1410-1可能是凹凸阶段的红色巨型分支（RGB）恒星，而TYC 2825-596-1很可能是核心氦燃烧的红色团（RC）恒星。两种光谱的线曲线表明，这两个富含Li的巨人是缓慢的旋转器，并且不显示红外（IR）过量。我们得出的结论是，吞噬不是这两颗恒星的锂富集机制。 TYC 1338-1410-1的富集锂可以通过Cameron-Fowler机制创建，而TYC 2825-596-1中的锂过量可能与非统计混合过程或He-Flash相关。
Two Li-rich candidates, TYC 1338-1410-1 and TYC 2825-596-1, were observed with the new high-resolution echelle spectrograph, LAMOST/HRS. Based on the high-resolution and high-signal-to-noise ratio (SNR) spectra, we derived stellar parameters and abundances of 14 important elements for the two candidates. The stellar parameters and lithium abundances indicate that they are Li-rich K-type giants, and they have A(Li)$_\mathrm{NLTE}$ of 1.77 and 2.91 dex, respectively. Our analysis suggests that TYC 1338-1410-1 is likely a red giant branch (RGB) star at the bump stage, while TYC 2825-596-1 is most likely a core helium-burning red clump (RC) star. The line profiles of both spectra indicate that the two Li-rich giants are slow rotators and do not show infrared (IR) excess. We conclude that engulfment is not the lithium enrichment mechanism for either star. The enriched lithium of TYC 1338-1410-1 could be created via Cameron-Fowler mechanism, while the lithium excess in TYC 2825-596-1 could be associated with either non-canonical mixing processes or He-flash.
