银河系中球状星团的空间运动

The Space Motion of Globular Clusters in the Galaxy

球状星团是银河系中最古老的天体类型之一，其累积光度很大，是银晕中重要的示踪天体。已经发现的银河系球状星团有１４０多个，其中１２０个银心距 Ｒ＜ ４０ ｈｐｃ的星团已被准确地测定了视向速度。根据这些数据以及球状星团金属度的统计分析，可以把球状星团次系再进一步分成某些不同的族群。目前已经测定过绝对自行的球状星团只有３８个。尽管这些自行的精度比视向速度和距离的精度差很多，然而，由此可以得出三维的空间速度，在统计上显露出一些很有意义的结果。Ｈｉｐｐａｒｃｏｓ星表的建立，将有可能把球状星团自行的测定直接建立在这一星表所体现的国际天球参考架之上，使得对球状星团空间运动的研究具有更坚实的基础，为银河系结构和早期演化研究作出更重要的贡献。

Globular clusters are ones of the most ancient objects in the Galaxy. They are very important tracers in the Galactic halo due to their high accumulated luminosity. Today, about more than 140 globular clusters in the Galaxy are observed. Radial velocities of 120 globular clusters within galactocentric distances R<40kpc are accurately determined. These globular clusters can be subdivided into some groups based on their radial velocities and metallicities. Up to now, only 38 globular clusters' absolute proper motions are determined. The accuracy of these Values is much lower than that of the radial velocities and distances. Using these data above, however, some interesting results have been attained from the three-dimensional space motions of these globular clusters. At present, it become possible to determine the absolute proper motions of globular clusters based on the International Celestial Reference name, optically represented by the new reference frame established by Hipparcos. It is of importance for the study of space motions of globular clusters and of the structure and earlier evolution of the Galaxy.