The Wolf 630 moving group of stars

An analysis is made of the probability of collective membership of the stars assigned by Eggen to the Wolf 630 moving group. This probability is estimated from the scatter of points in the colour-absolute magnitude diagram when compared to the intrinsic scatter observed for M67. Particular attention is paid to the random errors for all the observed and deduced stellar parameters. Results show that either the observational errors must be about 2.4 times larger than given in the proper motion and radial velocity source catalogues, or the intrinsic scatter in the colour-magnitude diagram for the Wolf 630 group must be much larger than for M67, or many of the stars considered cannot be members. (author)