ON THE STATUS OF PLANETARY-NEBULAE WITH WR-TYPE NUCLEI

A recent systematic search of Wolf-Rayet features in the spectra of Ga lactic planetary nebulae has increased the list of objects that are kn own to have WR-type nuclei to about 50. We have compared their nebular properties with those of the other planetary nebulae in the Galaxy. W e have found that the nebular morphological types are similarly distri buted in the two groups. Bipolar nebulae constitute only 20% of the to tal in each group. The distribution of the nebular abundance ratios N/ O, He/H and C/O are the same in the two groups. The nebular expansion velocities are larger in the group of planetary nebulae with WR centra l stars. We argue that the WR phenomenon does not preferentially occur in more massive central stars of planetary nebulae, contrarily to wha t has been suggested in some former studies.