RADIAL-VELOCITIES IN THE REGION OF CR-135

Continuing our work on radial velocities in some open cluster fields i n the Southern Hemisphere, we give mean radial velocities of 63 stars belonging to a 2-degrees X 2-degrees field centered on Cr 135 in Puppi s, where only a few radial velocities of bright stars are at present k nown. The plates have been taken with the 40-cm Objective Prism of ESO at La Silla, in Chile, and measured at the Observatoire de Haute-Prov ence, in France, with a cross-correlation method. The dispersion of th e instrument is 110 angstrom mm-1. We obtained relative radial velocit ies which have been fitted to the IAU standard system of radial veloci ties by means of some stars with already known radial velocities. We p resent the histogram of the errors and a general radial-velocity diagr am, as well as a discussion about the possible variable stars and the cluster membership. The histogram of the errors (E = square-root SIGMA epsilon2/[N(N-1)] shows a maximum between E=2.0 and E=3.0 km s-1 for a n average of six plates per star. The general radial-velocity diagram has a peak at about 20 km s-1 representing principally the field stars . The radial velocities of the five brightest stars and those of stars previously selected as probable cluster members lie in this peak. On the basis of photometric data, the physical reality of Cr 135 has been contested. Our results show that if, nevertheless, the cluster exists , its radial velocity is very close to that of field stars. Cr 135 cou ld also belong to an old association or to a stellar group.