论文标题
通过裸眼星的星星学$ν$ indi的星空学合并的早期经历的年龄约会
Age dating of an early Milky Way merger via asteroseismology of the naked-eye star $ν$ Indi
论文作者
论文摘要
在历史的过程中，银河系吸收了多个较小的卫星星系。尽管这些积聚的恒星种群可以被法医识别为银河系中的运动学不同的结构，但通常很难确切地与任何一个合并发生的年龄相比。最近的结果表明，通过矮星系的碰撞（称为\ textit {gaia} - 塞拉多斯）碰撞的恒星人群，导致对银河系的化学和动力学性质的实质性污染。在这里，我们将非常明亮的裸眼星$ν$ \，Indi确定为探究星系早期原位人口的年龄。 We combine asteroseismic, spectroscopic, astrometric, and kinematic observations to show that this metal-poor, alpha-element-rich star was an indigenous member of the halo, and we measure its age to be $11.0 \pm 0.7$ (stat) $\pm 0.8$ (sys)$\,\rm Gyr$.恒星带有标志性的标志，与\ textit {gaia} -Enceladus碰撞相一致。它的年龄意味着合并最早开始的时间分别为11.6和13.2 Gyr，分别为68％和95％的信心。基于层次宇宙学模型的计算的输入会稍微收紧上述限制（即减少）。
Over the course of its history, the Milky Way has ingested multiple smaller satellite galaxies. While these accreted stellar populations can be forensically identified as kinematically distinct structures within the Galaxy, it is difficult in general to precisely date the age at which any one merger occurred. Recent results have revealed a population of stars that were accreted via the collision of a dwarf galaxy, called \textit{Gaia}-Enceladus, leading to a substantial pollution of the chemical and dynamical properties of the Milky Way. Here, we identify the very bright, naked-eye star $ν$\,Indi as a probe of the age of the early in situ population of the Galaxy. We combine asteroseismic, spectroscopic, astrometric, and kinematic observations to show that this metal-poor, alpha-element-rich star was an indigenous member of the halo, and we measure its age to be $11.0 \pm 0.7$ (stat) $\pm 0.8$ (sys)$\,\rm Gyr$. The star bears hallmarks consistent with it having been kinematically heated by the \textit{Gaia}-Enceladus collision. Its age implies that the earliest the merger could have begun was 11.6 and 13.2 Gyr ago at 68 and 95% confidence, respectively. Input from computations based on hierarchical cosmological models tightens (i.e. reduces) slightly the above limits.
