论文标题
Wiyn开放群集研究LXXXI。被抓住了吗？奇特的红色巨人NGC 2243-W2135
WIYN Open Cluster Study LXXXI. Caught in the Act? The Peculiar Red Giant NGC 2243-W2135
论文作者
论文摘要
在LI 6708 Angstrom区域中的转弯恒星中，巨人的高分散光谱在旧的，金属缺陷的开放式群集NGC 2243中得到了分析。巨人是其亮度的最红色恒星，在天数的时间尺度上以最小0.1 mag水平显示出可变性，是单层的径向速度变量，并且在35至40 km/sec之间的V_SIN（i）（i）。与大多数红色巨型集群成员形成鲜明对比的是，该恒星具有可检测到的Li丰度，可能比迄今为止在通常采用的边界或低于通常采用的富含Li-Rich巨人的边界时所观察到的其他巨人。观察到的异常可能是巨人实现其不寻常的li丰度的基本过程的指标，而最近的传质发作是当前有限的约束中最可能的。
High-dispersion spectra for giants through turnoff stars in the Li 6708 Angstrom region have been obtained and analyzed in the old, metal-deficient open cluster, NGC 2243. When combined with high dispersion data from other surveys, the cluster is found to contain a uniquely peculiar star at the luminosity level of the red clump. The giant is the reddest star at its luminosity, exhibits variability at a minimum 0.1 mag level on a timescale of days, is a single-lined, radial-velocity variable, and has V_sin(i) between 35 and 40 km/sec. In sharp contrast with the majority of the red giant cluster members, the star has a detectable Li abundance, potentially as high or higher than other giants observed to date while at or just below the boundary normally adopted for Li-rich giants. The observed anomalies may be indicators of the underlying process by which the giant has achieved its unusual Li abundance, with a recent mass transfer episode being the most probable within the currently limited constraints.
