Abstract. Astrometry and BVRI CCD photometry of 115 stars down to B = 17.6 in the region of about 11 × 11 around the globular cluster NGC 4147 was performed. In the astrometric reduction, three earlier epoch plates taken at Sheshan, Shanghai, China, in 1958 and four recent epoch B-passband CCD frames taken at Kavalur, India, were used. The data were reduced to a catalogue based on measurements of stars on seven plates with an epoch period from 1917 to 1979 taken in Bonn, Germany, and ultimately to the Hipparcos catalogue. The reduction was done with the central overlapping method. Based on the new proper motion data, the membership probabilities of 115 stars were determined. Furthermore, three colourmagnitude diagrams (CMD) of V versus B − V , V − R and V − I, respectively, for HB and GB stars were constructed from CCD photometry obtained with the Vainu Bappu Telescope. An absolute proper motion of the cluster of −2.08 ± 0.48 mas/yr in right ascension and −3.07 ± 0.46 mas/yr in declination has been obtained. The space velocity and apogalactic distance of the cluster with respect to the Galactic standard of rest were calculated. In contrast to the first results given in the literature we obtain a significantly lower velocity and a smaller apogalactic distance for NGC 4147.
Abstract. 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.
Positions and absolute proper motions of 264 stars in the field of about 70′ × 70′ around the globular cluster M13 were determined. In the astrometric reduction, three early and three late epoch plates taken with the 40cm refractor at Shensan, Shanghai, China, were used, with the time baseline of 73 years. The reduction was done using the central overlapping algorithm, with 5 Hipparcos stars and 38 Tycho-2 stars used as reference stars. Based on the reduced proper motion data, the membership probabilities of the sample stars were determined. An absolute proper motion of the cluster of 1.49 ± 0.36 mas yr−1 in right ascension and 3.06±0.35 mas yr−1 in declination was obtained. From this proper motion, together with distance and radial velocity data, we derived the space motion of M13 and via numerical integration also the orbit of the cluster in the Galaxy.
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