THE SPATIAL STRUCTURE OF YOUNG STELLAR CLUSTERS. II. TOTAL YOUNG STELLAR POPULATIONS
THE SPATIAL STRUCTURE OF YOUNG STELLAR CLUSTERS. II. TOTAL YOUNG STELLAR POPULATIONS
复制标题
年轻恒星团的空间结构。
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
E. Feigelson
中科院分区：
文献类型：
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作者：
M. Kuhn;K. Getman;E. Feigelson
我们调查的内在恒星人口（估计总数的OB和前主序星下降到0.1兆？>）存在于MYStIX项目调查的17个大质量恒星形成区（MSFR）中。该研究基于超过31，000个MYStIX可能复合体成员的目录，这些成员具有盘状和非盘状种群，补偿了灭绝，星云和拥挤效应。观测灵敏度的校正是用X射线光度函数和近红外初始质量函数来进行的，这是一种通常不会用年轻恒星的红外巡天来进行的校正。由此产生的年轻恒星群体的投影结构图，在单位的内在恒星表面密度，允许不同地区之间的直接比较。有几个区域有多个致密的团块，在大小和密度上与猎户座星云团相似。在RCW 38星团的核心发现了最高密度的投影，约有134，000颗恒星pc−2。表面密度的直方图显示了不同区域的不同数值范围，支持了Bressert等人的结论，即没有通用的表面密度阈值可以区分集群和分布式星星的形成。然而，很大一部分年轻的MSFR恒星群居住在200- 10，000颗恒星pc−2的密集环境中（包括附近的猎户座分子云），我们发现没有证据支持B10的结论，即这样的密集区域形成了分布的极端“尾部”。这些地区的固有人口表中使用的年轻集群的性质和演化的同伴研究。
We investigate the intrinsic stellar populations (estimated total numbers of OB and pre-main-sequence stars down to 0.1 M ⊙ ?> ) that are present in 17 massive star-forming regions (MSFRs) surveyed by the MYStIX project. The study is based on the catalog of >31,000 MYStIX Probable Complex Members with both disk-bearing and disk-free populations, compensating for extinction, nebulosity, and crowding effects. Correction for observational sensitivities is made using the X-ray luminosity function and the near-infrared initial mass function—a correction that is often not made by infrared surveys of young stars. The resulting maps of the projected structure of the young stellar populations, in units of intrinsic stellar surface density, allow direct comparison between different regions. Several regions have multiple dense clumps, similar in size and density to the Orion Nebula Cluster. The highest projected density of ∼34,000 stars pc−2 is found in the core of the RCW 38 cluster. Histograms of surface density show different ranges of values in different regions, supporting the conclusion of Bressert et al. that no universal surface-density threshold can distinguish between clustered and distributed star formation. However, a large component of the young stellar population of MSFRs resides in dense environments of 200–10,000 stars pc−2 (including within the nearby Orion molecular clouds), and we find that there is no evidence for the B10 conclusion that such dense regions form an extreme “tail” of the distribution. Tables of intrinsic populations for these regions are used in our companion study of young cluster properties and evolution.