SIMBAD references

A recent systematic search of Wolf-Rayet features in the spectra of Galactic planetary nebulae has increased the list of objects that are known to have WR-type nuclei to about 50. We have compared their nebular properties with those of the other planetary nebulae in the Galaxy. We have found that the nebular morphological types are similarly distributed in the two groups. Bipolar nebulae constitute only 20% of the total 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 central stars. We argue that the WR phenomenon does not preferentially occur in more massive central stars of planetary nebulae, contrarily to what has been suggested in some former studies.