A proper motion study of the globular cluster M 10

We present the first proper motion study of M 10 (NGC 6254). Absolute proper motions of about 532 stars in the field of the globular cluster M 10 were determined with respect to Hipparcos and ACT reference stars. In addition to photographic plates of Bonn and Shanghai also wide field CCD observations as second epoch plates were used. The wide field CCD observations show an accuracy comparable to that of the photographic plates. A good coincidence of the solutions based on reference stars from Hipparcos and from ACT was found. Our final proper motions allow a sufficient separation of cluster and field stars. Two population II Cepheids were confirmed to be members of M 10. The absolute proper motion of M 10 was determined and combined with its distance from the Sun and its radial velocity. The space motion and metallicity of M 10 indicates the characteristics of a halo object with an orbit reaching to a maximal z-distance of less than 3 kpc.