Star formation in groups
Star formation in groups
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DOI：
10.1093/mnras/272.1.213
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发表时间：
1995
影响因子：
4.8
通讯作者：
R. Larson
中科院分区：
文献类型：
--
作者：
R. Larson
为了研究成团和双星形成之间的关系，Gomez等人对金牛座地区年轻恒星成团的分析已经扩展到更小的分离，通过使用最近搜索这些恒星的近伴星的数据。金牛座年轻的恒星被发现表现出自相似或分形聚类的最大尺度上，但有一个明显的突破，从自相似性在约0.04 pc的规模划分制度的二进制和多个系统在较小的尺度上，从真正的集群在较大的尺度上。这种破裂为星星形成过程中存在内禀尺度提供了明确的证据，并且发现这种尺度基本上等于典型分子云核中的金斯长度。相关质量是一个太阳质量的数量级，支持典型恒星质量由金斯质量决定的假设。金牛座恒星在较大尺度上的自相似聚类和上恒星IMF的幂律形式都可能起源于等级，也许是分形的云结构。在双星系统和多星系统中观察到的恒星间距分布非常不同，这强烈表明这些系统的形成方式与等级星团不同，而是通过一种独特的机制形成的，这种机制可能是由大约金斯大小的坍缩团块破碎而成。证据表明，几乎所有的恒星都是在双星或多星系统中形成的，其中一些系统随后被更密集的恒星形成环境中的相互作用破坏，产生了观察到的单星，双星和多星的混合物。
In order to study the relation between clustering and binary formation, the analysis by Gomez et al. of the clustering of young stars in the Taurus region has been extended to smaller separations by using data from recent searches for close companions to these stars. The Taurus young stars are found to exhibit self-similar or fractal clustering on the largest scales, but there is a clear break from self-similarity at a scale of about 0.04 pc which divides the regime of binary and multiple systems on smaller scales from that of true clustering on larger scales. This break provides clear evidence for the existence of an intrinsic scale in the star formation process, and this scale is found to be essentially equal to the Jeans length in typical molecular cloud cores. The associated mass is of the order of one solar mass, supporting the hypothesis that typical stellar masses are determined by the Jeans mass. Both the self-similar clustering of the Taurus stars on the larger scales and the power-law form of the upper stellar IMF may have their origin in hierarchical, and perhaps fractal-like, cloud structure. The very different distribution of stellar separations that is observed in the regime of binary and multiple systems strongly suggests that these systems are not formed in the same way as the hierarchical clustering, but by a distinct mechanism which is probably the fragmentation of collapsing clumps of about the Jeans size. The evidence suggests that nearly all stars are formed in binary or multiple systems, and that some of these systems are subsequently disrupted by interactions in the denser star-forming environments to produce the observed mixture of single, binary and multiple stars.