Common Proper Motion Stars in a Southern Zone Catalogue

Extract

In the recent Yale Zone Catalogues star charts have been included showing 20,000 year changes in star positions indicated by the proper motions of the catalogued stars. An inspection of such charts (e.g. Figure 1) reveals some widely scattered stars which seem to share large proper motions. In the Zone Catalogue for -40° to -50°, just published as Vol. 30 of the Transactions of the Yale University Observatory, we have indicated some fifty pairs or groups of stars appearing to have closely the same proper motions exceeding 0.”100. The numbers of stars represented in each group range from two to fifty. In general, the largest groups correspond to the smallest motions, where the uncertainties are also the greatest. The average number of stars per group decreases from eleven for proper motions between 0.”100 and 0.”200, to three between 0.”300 to 0.”500, to two for proper motions exceeding 0.”500.