The hierarchical formation of a stellar cluster
The hierarchical formation of a stellar cluster
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DOI：
10.1046/j.1365-8711.2003.06687.x
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发表时间：
2003-08-01
影响因子：
4.8
通讯作者：
Vine, SG
中科院分区：
文献类型：
--
作者：
Bonnell, IA;Bate, MR;Vine, SG
最近对恒星形成区域的调查表明，大多数恒星，可能是所有的大质量恒星，都是在密集的星团中诞生的。分子云分裂形成数百到数千颗独立恒星的机制仍然难以捉摸。在这里，我们使用数值模拟来跟踪湍流分子云的破碎，以及随后包含400多颗恒星的星团的形成和早期演化。我们展示了星团是通过湍流分子云的分层破碎形成的。这导致了许多小的子星团的形成，这些子星团相互作用并合并形成最终的星团。星团形成的层次性对新生恒星的性质有着严重的影响。与整体形成形成的更均匀的分布相比，亚星团中恒星的数量密度更高，导致更紧密和更频繁的动态相互作用。这种密切的相互作用可以截断星周盘，使现有的双星变硬，并可能解放行星种群。我们估计，至少有三分之一的恒星，以及大多数大质量恒星，遭受了这种破坏性的相互作用。
Recent surveys of star-forming regions have shown that most stars, and probably all massive stars, are born in dense stellar clusters. The mechanism by which a molecular cloud fragments to form several hundred to thousands of individual stars has remained elusive. Here, we use a numerical simulation to follow the fragmentation of a turbulent molecular cloud, and the subsequent formation and early evolution of a stellar cluster containing more than 400 stars. We show that the stellar cluster forms through the hierarchical fragmentation of a turbulent molecular cloud. This leads to the formation of many small subclusters, which interact and merge to form the final stellar cluster. The hierarchical nature of the cluster formation has serious implications in terms of the properties of the new-born stars. The higher number-density of stars in subclusters, compared to a more uniform distribution arising from a monolithic formation, results in closer and more frequent dynamical interactions. Such close interactions can truncate circumstellar discs, harden existing binaries and potentially liberate a population of planets. We estimate that at least one-third of all stars, and most massive stars, suffer such disruptive interactions.