The proper and space motions of the globular cluster NGC 4147 on the Hipparcos system

摘要

Dr M. Geffert, of Sternwarte der Universitat Bonn, kindly provided us with the positions and proper motions of 82 stars in the field of the globular cluster NGC 4147, reduced with 11 reference stars from the Hipparcos catalogue. We used 54 of these stars to re-reduce the observations by Wang Jia-ji and Gupta. Based on the new proper motion obtained from this reduction, a new absolute proper of the cluster, (-2.08 ± 0.48, -3.07 ± 0.46) mas/yr, is found (including a possible systematic error of 0.25 mas/yr for the Hipparcos Catalogue system). An apogalactic distance of 22.5 kpc is found for the cluster from the new space motion.