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arXiv 1806.04824astro-ph.GA
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Terzan 5内多个恒星星族的新模型

A new model for the multiple stellar populations within Terzan 5

Madeleine McKenzie, Kenji Bekki

摘要:

最近的观测研究表明,复杂的恒星系统Terzan 5(Ter 5)拥有多个恒星群。有几个模型试图解释几个Gyrs的优势种群之间的巨大年龄差异,但没有被普遍接受。我们提出了一个新的方案,即一个贫金属的Ter 5和一个巨大的分子云(GMC)之间的碰撞作为一个超级太阳的恒星群体的产生的催化剂。使用这种新的“GC-GMC”碰撞场景的数值模拟,我们证明,在几个陀螺仪的时间范围内,我们的合成Ter 5能够与银河系中心区域的富含金属的GMC相互作用。因此,我们模拟的球状星团(GC)能够从碰撞的GMC中捕获足够的气体,形成新的富含金属的恒星。此外,从捕获气体的高密度区域产生的年轻人口显示出比旧的贫金属人口具有更强的中心质量浓度,这与观测结果一致。Ter 5和银河系核球之间的化学联系一直被观察到,这些模拟最终为它们的相似性提供了证据。我们的模型合理化的5 Gyrs之间观察到的两个占主导地位的人口Ter 5的静止,并证明了年轻一代的存在。我们讨论的优点和缺点的新方案中观察到的物理性质的Ter 5的上下文中。

英文摘要:

Recent observational studies have demonstrated that the complex stellar system Terzan 5 (Ter 5) harbours multiple populations of stars. Several models have attempted to interpret the large age difference of several Gyrs between the dominant populations, but none have been universally accepted. We propose a new scenario whereby a collision between a metal-poor Ter 5 and a giant molecular cloud (GMC) serves as a catalyst for the generation of a super-solar population of stars. Using numerical simulations of this new "GC-GMC" collision scenario we demonstrate that, within a time frame of several Gyrs, our synthetic Ter 5 was capable of interacting with a metal-rich GMC in the central region of the Galaxy. As a consequence of this, our simulated globular cluster (GC) is able to capture enough gas from the colliding GMC to form a new population of metal-rich stars. Furthermore, the younger population created from the high-density regions of the captured gas is shown to have a stronger central mass concentration than the older metal-poor one, which is consistent with observations. A chemical link between Ter 5 and the bulge population of the Milky Way has long been observed and these simulations finally provide evidence for their similarities. Our model rationalises the 5 Gyrs of quiescence observed between the two dominant populations of Ter 5 and justifies the existence of the young generation. We discuss the advantages and disadvantages of the new scenario in the context of the observed physical properties of Ter 5.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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