疏散星团M67成员星的两点相关分析

对著名老年疏散星团M67的成员星进行了两点相关函数分析,讨论了团星的空间分布情况及质量分层现象.结果表明:M67成员星的两点相关函数能很好地用幂律形式来描述,其成员星在空间分布上具有显著的成团性和自相似性.对M67不同光度成员星两点自相关函数的分析表明,亮星相比暗星具有更强的相关强度和更大的相关指数,说明在星团内部出现了明显的空间质量分层现象,亮星比暗星具有更强的成团性和更大的中心聚度.不同光度成员星间两点交叉相关函数的分析进一步表明,不同光度成员星之间并没有表现出绝对的空间质量分层现象,亮星和暗星在空间分布上相互交织、相互渗透.

Two-point Correlation Function of Member Stars in the Open Star Cluster M67

In this paper, we study the two-point correlation function of the old open cluster M67. We discuss the spatial distribution and mass segregation of M67 member stars. The result suggests that spatial distribution of all member stars can be well described by power law. This implies that M67 is characterized by significant spatial clustering and self-similarity. The result of two-point self-correlation function analysis shows that brighter member stars tend to have greater correlation strength and larger correlation index. This indicates that the spatial mass segregation in M67 exists and brighter stars have larger spatial concentration. Further cross-correlation analysis reveals that there is no absolute mass segregation for M67 member stars and all of stars mingle with each other in spatial distribution.