在疏散星团M67中发现一颗高速星

Discovery of a high-velocity star in the open cluster M67

利用UCAC4星表（the fourth U.S. naval observatory CCD astrograph catalog）提供的高精度自行数据分析了疏散星团M67的运动学性质. 分析显示有1颗质量约0.8~0.9 Mo的小质量恒星以约30±；9 km/s的高速相对于星团运动. 这颗高速星距星团中心的投影距离约0.4 pc， 位于星团核心区. 其速度是星团核心区理论逃逸速度的16倍， 处于高速逃逸状态. 该星在颜色-星等图上的位置、空间投影位置以及视向速度表明它极有可能是M67的成员星. 在M67中发现高速星对理解星团内部动力学演化以及太阳系的起源都有重要意义.

We report the discovery of a high-velocity star in the core of open cluster M67, located at a project distance of about 0.4 pc from the cluster center. The star has a tangential velocity of about 30＋9 km/s relative to the cluster, corresponding to 16 times of the escape velocity in the core, which is only about 1.9 km/s. The high-velocity star is estimated to have a mass of 0.8-0.9 Mo, and no evidence indicates that the star is in a binary system. The position in color-magnitude diagram, project distance from the cluster center and the radial velocity indicate that the star is very likely a member star of the cluster.