The nature of the lithium enrichment in the most Li-rich giant star
The nature of the lithium enrichment in the most Li-rich giant star
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最富锂巨星中锂富集的性质
DOI：
10.1038/s41550-018-0544-7
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发表时间：
2018
期刊：
影响因子：
14.1
通讯作者：
Gang Zhao
中科院分区：
文献类型：
--
作者：
Hong-Liang Yan;Jiang-Rong Shi;Yu-Tao Zhou;Yong-Shou Chen;Er-Tao Li;Suyalatu Zhang;Shao-Lan Bi;Ya-Qian Wu;Zhi-Hong Li;Bing Guo;Wei-Ping Liu;Qi Gao;Jun-Bo Zhang;Ze-Ming Zhou;Hai-Ning Li;Gang Zhao
大约1%的巨型\upcite{Brown 1989}在其大气中被检测到具有非常高的锂（Li）丰度，与标准恒星演化模型\upcite{Iben 1967}的预测直接冲突，并使Li的产生和演化更加有趣，不仅在大爆炸核合成\upcite{Cyburt 2016}的意义上，Spite 1982}或银河系介质\upcite{Tajitsu 2015}，但也是恒星的演化。几十年来，人们一直在努力解释为什么存在这样的异常值，但富锂巨星的起源仍然存在争议。在这里，我们报告了迄今为止发现的最富锂的巨人，具有超高的锂丰度4.51。这一罕见的现象与另一个短期事件一起被抓拍到，该事件是星星在红巨星分支上经历的光度颠簸。如此高的锂丰度表明该星星可能正处于富锂阶段的初期，这为研究银河系中锂的起源和演化提供了一个很好的机会。一个详细的核模拟与最新的反应速率，以重现在这个星星的锂富集过程。我们的研究结果提供了严格的约束，观测和理论的观点，这表明低质量的巨人可以产生自己的超高水平的红巨星阶段期间通过运输锂。
About one percent of giants\upcite{Brown1989} are detected to have anomalously high lithium (Li) abundances in their atmospheres, conflicting directly with the prediction of the standard stellar evolution models\upcite{Iben1967}, and making the production and evolution of Li more intriguing, not only in the sense of the Big Bang nucleosynthesis\upcite{Cyburt2016,Spite1982} or the Galactic medium\upcite{Tajitsu2015}, but also the evolution of stars. Decades of efforts have been put into explaining why such outliers exist\upcite{Sackmann1999, Denissenkov2004, Charbonnel2010}, yet the origins of Li-rich giants are still being debated. Here we report the discovery of the most Li-rich giant known to date, with a super-high Li abundance of 4.51. This rare phenomenon was snapshotted together with another short-term event that the star is experiencing its luminosity bump on the red giant branch. Such high Li abundance indicates that the star might be at the very beginning of its Li-rich phase, which provides a great opportunity to investigate the origin and evolution of Li in the Galaxy. A detailed nuclear simulation is presented with up-to-date reaction rates to recreate the Li enriching process in this star. Our results provide tight constraints on both observational and theoretical points of view, suggesting that low-mass giants can produce Li inside themselves to a super high level viaBe transportation during the red giant phase.