当前观测到的团块不可能是当前观测到的疏散星团的“直接”前身
The currently observed clumps cannot be the "direct" precursors of the currently observed open clusters
AI总结：
通过比较团块、嵌入星团与疏散星团的质量和半径，研究发现单团块直接演化无法解释年老高质量疏散星团，并支持多嵌入星团气体抛射后并合等起源。
摘要：
我们对团块、嵌入星团和疏散星团进行了分类，并对它们的物理性质开展了比较分析。总体而言，疏散星团的半径显著大于嵌入星团和团块。嵌入星团的半径大于团块，这可能源于嵌入星团的膨胀。疏散星团的质量显著高于嵌入星团，约高出一个数量级。鉴于银河系中团块当前的质量分布，由单个团块演化为嵌入星团、随后再演化为疏散星团的演化序列无法解释观测到的年老且高质量的疏散星团；对单个嵌入星团的N体模拟也支持这一点。为解释观测到的疏散星团的质量和半径分布，必须拥有质量高于3000 M$_{\odot}$的初始嵌入星团。然而，嵌入星团样本的质量上限低于1000 M$_{\odot}$，而且只有少数ATLASGAL团块的质量高于3000 M$_{\odot}$。因此，当前观测到的团块不可能是当前观测到的疏散星团的“直接”前身。如果银河系具有爆发式且随时间变化的恒星形成历史，那么当前观测到的年老且高质量的疏散星团可能来自过去的大质量团块。另一种非常现实的可能性是，这些疏散星团起源于气体抛射后多个嵌入星团的并合。我们比较了疏散星团的间距与分子云的典型尺度，发现大多数分子云可能只形成一个疏散星团，这支持气体抛射后并合的情景。要区分这些不同情景，仍需进一步研究。
英文摘要：
We categorized clumps, embedded clusters, and open clusters and conducted a comparative analysis of their physical properties. Overall, the radii of open clusters are significantly larger than those of embedded clusters and clumps. The radii of embedded clusters are larger than those of clumps, which may be due to the expansion of embedded clusters. The open clusters have significantly higher masses than embedded clusters, by about one order of magnitude. Given the current mass distribution of clumps in the Milky Way, the evolutionary sequence from a single clump evolving into an embedded cluster and subsequently into an open cluster cannot account for the observed open clusters with old ages and high masses, which is also supported by N-body simulations of individual embedded clusters. To explain the mass and radius distributions of the observed open clusters, initial embedded clusters with masses higher than 3000 M$_{\odot}$ are necessary. However, the upper limit of the embedded cluster sample is less than 1000 M$_{\odot}$, and only a few ATLASGAL clumps have a mass higher than 3000 M$_{\odot}$. Thus, the currently observed clumps cannot be the "direct" precursors of the currently observed open clusters. If the Milky Way has a burst-like and time-dependent star formation history, the currently observed open clusters with old ages and high masses may come from massive clumps in the past. There is also a very real possibility that these open clusters originate from post-gas expulsion coalescence of multiple embedded clusters. We compared the separation of open clusters and the typical size of molecular clouds, and find that most molecular clouds may only form one open cluster, which supports the scenario of post-gas expulsion coalescence. Further study is necessary to distinguish between the different scenarios.
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。
