标题： 中等至低质量星团中的恒星以及锂的演化 显示英文标题

标题： Intermediate-to-Low Mass Stars in Open Clusters and the Evolution of Li

摘要： 疏散星团（OC）年龄为1-3 Gyr，包含处于多种与理解锂演化相关的演化阶段的中等至低质量恒星。 从锂凹陷（LD）的热侧离开主序星（MS）的恒星，在固定年龄下可能包含不同质量、不同程度的核心简并以及在平静或闪光条件下的氦点燃。 对关键疏散星团中从巨星分支到锂凹陷以下的大量恒星进行的持续调查揭示了模式，这些模式提供了关于不同质量和年龄恒星之间锂变化潜在来源的关键线索。 尽管在这一年龄的OC中锂凹陷（LD）已被很好地确立，但位于锂凹陷热侧的恒星在颜色-光度图（CMD）的同一区域中，其锂含量可以从明显的原始星团值变化到类似于锂凹陷中心发现的上限。 首次上升的巨星分支上的恒星显示出可测量锂的显著下降，这与年龄增加和减少的转折质量密切相关。 我们讨论了这些趋势如何在锂凹陷本身的存在以及单个恒星时间演化背景下得到解释。 显示英文摘要

摘要： Open clusters (OC) of 1-3 Gyr age contain intermediate-to-low-mass stars in evolutionary phases of multiple relevance to understanding Li evolution. Stars leaving the main sequence (MS) from the hot side of the Lithium dip (LD) at a fixed age can include a range of mass, varying degrees of core degeneracy, and helium ignition under quiescent or flash conditions. An ongoing survey of a significant sample of stars from the giant branch to below the LD in key open clusters has revealed patterns that supply critical clues to the underlying source of Li variation among stars of differing mass and age. While the LD is well established in OC of this age, stars on the hot side of the LD can exhibit Li ranging from the apparent primordial cluster value to upper limits similar to those found at the LD center, despite occupying the same region of the color-magnitude diagram (CMD). Stars on the first-ascent giant branch show a dramatic decline in measurable Li that correlates strongly with increasing age and reduced turnoff mass. We discuss how these trends can be explained in the context of the existence of the LD itself and the temporal evolution of individual stars.