论文标题
氦气诱导的混合事件可以解释红色团星的锂丰度
A helium-flash-induced mixing event can explain the lithium abundances of red clump stars
论文作者
论文摘要
观察结果表明，低质量恒星中$^7 {\ rm li} $的表面丰度在红色巨型分支和红色团块的尖端之间发生了巨大变化。这自然表明与这两个阶段之间发生的氦芯闪光相关。使用恒星演化模型和简单的临时混合处方，我们证明了$^7 {\ rm li} $增强功能可以通过简短的化学混合事件来解释，该事件发生在他第一次，最强的他亚闪存时发生。 $^7 {\ rm be} $的数量已经存在于闪光灯之前的H燃烧外壳上方，一旦将其混合到冷却器信封中，并经历电子捕获将其转换为$^7 {\ rm li} $，就足以解释在恢复物中观察到的丰度。我们建议在闪光期间通过剧烈的湍流对流激发内部重力波的激发可能会提供一种可以诱发这种混合的物理机制。
Observations demonstrate that the surface abundance of $^7{\rm Li}$ in low-mass stars changes dramatically between the tip of the red giant branch and the red clump. This naturally suggests an association with the helium core flash, which occurs between these two stages. Using stellar evolution models and a simple, ad hoc mixing prescription, we demonstrate that the $^7{\rm Li}$ enhancement can be explained by a brief chemical mixing event that occurs at the time of the first, strongest He sub-flash. The amount of $^7{\rm Be}$ already present above the H-burning shell just before the flash, once it mixes into the cooler envelope and undergoes an electron capture converting it to $^7{\rm Li}$, is sufficient to explain the observed abundance at the red clump. We suggest that the excitation of internal gravity waves by the vigorous turbulent convection during the flash may provide a physical mechanism that can induce such mixing.
