中文摘要：

老年球状星团和年轻的超星团是两类不同性质的致密星团,观测表明它们都表现出某种程度的质量分层效应。该文在介绍这两类星团质量分层的探测途径和观测表象的基础上,对形成这种分层效应的两种可能的机制——动力学分层和原初分层做了简要的讨论和评述.

英文摘要：

The phenomenon of mass segregation of a star cluster means a preferential concentration of high mass stars towards the cluster center and a preferential allocation of lower mass stars towards the periphery of the cluster,which seems to occur in star systems with widely distinct physical properties.As a kind of compact star systems,globular clusters are very old ones with ages of older than 10^10years,which are different from another kind of young compact clusters, super star clusters（SSC）or massive young clusters（MYC）,with ages ranging from a few 10^6 to 10^8 years.It is interesting that mass segregation of member stars has been observed for these two kinds of compact clusters. An important observational effect of mass segregation of a star cluster is expected that the slopeαof the PDMF（present day mass function）of the cluster is dependent on radial distance r from the cluster center,in the senseαbecoming steeper with r increasing.This radial variation of the mass function reveals mass segregation for both old globular clusters and young SSC or MYC.On the other hand,it is found that stars of different masses in a cluster show the pronounced,systematic variations of the core radius,which is another observational effect of mass segregation.Mass segregation mainly affects the innermost region of clusters,while dynamical interaction with the Galaxy acts predominantly their outermost regions inducing stellar evaporation and stripping. Further evidence of mass segregation in a globular cluster comes from the detection of color gradients whereby the color indices such as（U-B）or（B-V）get bluer towards the cluster center.A possible explanation for such color gradients is mass segregation of main sequence （MS）stars,since stars near the MS turnoff,with higher and bluer color,are expected to be more centrally concentrated than the fainter,redder,and lower mass stars.A core concentration of blue stars is likely due to binary-single star interaction or the central lack of low mass MS stars. Mass segreg