Enrichment by supernovae in globular clusters with multiple populations
Enrichment by supernovae in globular clusters with multiple populations
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DOI：
10.1038/nature08565
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发表时间：
2009-11
期刊：
影响因子：
64.8
通讯作者：
Jae-Woo Lee;Y. Kang;Jina Lee;Young-Wook Lee
中科院分区：
文献类型：
--
作者：
Jae-Woo Lee;Y. Kang;Jina Lee;Young-Wook Lee
银河系中质量最大的球状星系团，半人马座ω，被认为是一个分裂的矮星系的剩余核心，正如在分级合并模型中所预期的那样。它包含了几个由超新星提供的不同重元素丰度的恒星群体--这一过程被称为金属富集化。虽然M22看起来与ωCEN相似，但其他特殊的球状星系团却不是。因此，ωCEN和M22被认为是例外的，而其他星系团中化学不均匀的存在被视为来自正常球状星系团中预期的中等质量渐近巨星枝恒星的“污染”。在这里，我们报告了七个球状星系团的钙丰度，并与ωCEN进行了比较。钙和其他重元素只能通过这些恒星系统中的大质量恒星的无数次超新星爆炸来提供，但目前星系团的引力势不能保存这种爆炸产生的大部分抛射物。我们的结论是，这些球状星系团，像ωCEN一样，很可能是更大质量的原始矮星系的遗迹，这些星系合并和分裂形成了原始星系。
The most massive globular cluster in the Milky Way, ω Centauri, is thought to be the remaining core of a disrupted dwarf galaxy,, as expected within the model of hierarchical merging,. It contains several stellar populations having different heavy elemental abundances supplied by supernovae—a process known as metal enrichment. Although M 22 appears to be similar to ω Cen, other peculiar globular clusters do not,. Therefore ω Cen and M 22 are viewed as exceptional, and the presence of chemical inhomogeneities in other clusters is seen as ‘pollution’ from the intermediate-mass asymptotic-giant-branch stars expected in normal globular clusters. Here we report Ca abundances for seven globular clusters and compare them to ω Cen. Calcium and other heavy elements can only be supplied through numerous supernovae explosions of massive stars in these stellar systems, but the gravitational potentials of the present-day clusters cannot preserve most of the ejecta from such explosions. We conclude that these globular clusters, like ω Cen, are most probably the relics of more massive primeval dwarf galaxies that merged and disrupted to form the proto-Galaxy.