STUDY OF PROPER MOTIONS IN THE REGION OF THE OPEN CLUSTER M67 AND MEMBERSHIP OF STARS

Relative proper motions and membership probabilities of 1046 stars in the open cluster M67 area are determined from PDS measurements of 9 pl ate pairs taken with the double astrograph at the Zo-Se station of Sha nghai Observatory, which has an aperture of 40 cm, a focal length of 6 .9 m and a scale of 30''/mm. The number of stars with membership proba bilities higher than 0.8 and at a distance less than 45' from the fiel d center is 282. The average standard errors of proper motions vary fr om +/- 0.0004''/yr for bright stars in the inner part of the field to some +/- 0.0015''/yr for faint stars in the outer part of the cluster. It is shown by a detailed discussion that the proper motions and memb ership probabilities of the stars determined in this paper are in quit e satisfactory agreement with those obtained by Sanders (1977) or Gira rd et al. (1989).