论文标题

密集星团中三重系统的人口统计

Demographics of triple systems in dense star clusters

论文作者

Fragione, Giacomo, Martinez, Miguel A. S., Kremer, Kyle, Chatterjee, Sourav, Rodriguez, Carl L., Ye, Claire S., Weatherford, Newlin C., Naoz, Smadar, Rasio, Frederic A.

论文摘要

根据恒星类型的不同,超过$ \ sim 50 $ \%和$ \ sim 15 \%$ $ $ $ $ $ $ $ $分别具有至少一个和两个恒星伴侣。层次系统可以在恒星簇中动态组装,这是由于恒星之间的几个体内相遇和/或簇核中的紧凑型残留物。在本文中,我们介绍了通过\ texttt {cmc cluster目录}在\ texttt {cmc cluster目录中形成的恒星和紧凑型三元组的人口统计,这是一套群集模拟的套件,其中具有代表球状簇(GC)(GC)的当前属性的群集模拟。我们展示主机群集的初始特性如何设置形成三元组的典型轨道参数和形成时间。我们发现,一个簇通常在内部二进制中组装了数百个三元组,至少有一个黑洞(BH),而仅具有足够小的病毒半径的簇可以有效地产生带有BHS的三元组,这是由于BH燃烧过程的结果。我们表明,典型的GC目前将拥有至少一个发光成分的数十三倍。我们讨论了利多夫 - 科泽机制如何将形成的三元组的内部二进制驱动到高偏心率,每当发生在三重群体之前通过遇到另一个群集成员进行动态重新处理。其中一些系统可以达到足够大的偏心率,以形成各种瞬态和来源,例如蓝色stragglers,X射线二进制文件,IA型Supernovae,Thorne-Zytkow物体和Ligo/Pirgo来源。

Depending on the stellar type, more than $\sim 50$\% and $\sim 15\%$ of stars in the field have at least one and two stellar companions, respectively. Hierarchical systems can be assembled dynamically in dense star clusters, as a result of few-body encounters among stars and/or compact remnants in the cluster core. In this paper, we present the demographics of stellar and compact-object triples formed via binary--binary encounters in the \texttt{CMC Cluster Catalog}, a suite of cluster simulations with present-day properties representative of the globular clusters (GCs) observed in the Milky Way. We show how the initial properties of the host cluster set the typical orbital parameters and formation times of the formed triples. We find that a cluster typically assembles hundreds of triples with at least one black hole (BH) in the inner binary, while only clusters with sufficiently small virial radii are efficient in producing triples with no BHs, as a result of the BH-burning process. We show that a typical GC is expected to host tens of triples with at least one luminous component at present day. We discuss how the Lidov-Kozai mechanism can drive the inner binary of the formed triples to high eccentricities, whenever it takes place before the triple is dynamically reprocessed by encountering another cluster member. Some of these systems can reach sufficiently large eccentricities to form a variety of transients and sources, such as blue stragglers, X-ray binaries, Type Ia Supernovae, Thorne-Zytkow objects, and LIGO/Virgo sources.

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