PLANETARY-NEBULAE MORPHOLOGIES, CENTRAL STAR MASSES AND NEBULAR PROPERTIES

We have constituted a sample of about 80 PN with defined morphologies and well observed basic parameters (fluxes, angular radii, expansion v elocities and magnitudes of the central stars). For these PN, we have derived the central star masses by comparing the observed set of param eters with those predicted by a simple evolutionary model of a PN, exp anding at the same velocity as the observed one. We have then examined the relations between the PN morphological types and other properties , linked to the central star mass. Bipolar PN are shown to have a wide r distribution of central star masses than the rest of PN, and shifted towards higher values. They lie closer to the Galactic plane and tend to have larger N/O ratios. Point symmetric PN, which have not been mu ch studied so far, are found to constitute an outstanding class. They show an almost perfect M - upsilon(exp) correlation. They correspond to a rather short evolutionary stage of PN. They lie, on average, furt her from the Galactic plane than bipolar PN and tend to have lower N/O . Globally, PN with higher central star masses are found closer to the Galactic plane, and the observed relation between N/O and M is rough ly consistent with the predictions from evolutionary models for AGE st ars.