HIPPARCOS后的银河系距离尺度

Post-Hipparcos Galactic Distance Scales

应用《Hipparcos星表》中的自行和视差等数据，可以确定员星团、毕星团以及其它近距疏散星团的距离。对由此所得的结果以及由地面观测已得的结果作了评述，指出毕星团的距离问题已经圆满解决，等于（46．34±0．27）pc。可是，由Hipparcos定出的昂星团距离，却比最新的一些地面测定结果近了10％以上．另外，由Hipparcos定出的其他近距星团的距离，明显地分为两种情况，即由鬼星团、后发星团、英仙星团和Blanco1星团确定了一条主序，而易星团与IC2301和IC2602两个星团一起，得出了另一条主序，两者相比，后者暗了约0．5mag．这些问题与矛盾，有待于进一步的地面和未来的空间观测来解决。

A review about the distances of the Pleiades, the Hyades, and other nearby open clusters,which were determined based on the parallaxes and proper motions from the Hipparcos Catalogueand on previous ground-based observations, is given. It is noted that the problem about thedistance of the Hyades has been settled. On other hand, the distance of the Pleiades from theHipparcos is nearer about 10 % than recellt ground- based values. Furthermore, the distancesof some other open clusters from the Hipparcos are obviously divided two groups: the clustersPraesepe, Coma, Perseus and Blanco 1 determine a main sequence; otherwise, the clusters iC2301 and iC 2602 with the Pleiades determine another main sequence. Compared the two mainsequences, the latter is fainter about 0.5 mag. These open and new problems are described. Aprospect solving the problems by the further ground--based observations and the future spaceobservations is also given.