Mass Distribution and Birth Rate of Central Stars of Planetary Nebulae: Comparison with White Dwarfs, and Influence of Selection Effects

Abstract

The mass distribution of central stars (CPN) as derived by the Schonberner method (1981) Mvvs. age, v(exp) = const, for an enlarged local ensemble, as presented at the London Symposium, 1983, appears to be much narrower and more strongly peaked towards smaller masses than the one recently derived by Heap and Augensen (1987) (HA) using the same method, but IUE data and M(λ1300) vs. age, corrected for individual v(exp). Whereas according to Schonberner 65% of all CPN have M . 1.4 x CK. If one uses Barlow’s recalibration formula for optically thick PN, the distances for those — which mainly contribute to the massive CPN in the HA analysis — are increased so much as to remove most of them from the local ensemble. We thus obtain for the revised IUE ensemble 84% CPN with M<0.64 M ⊙, in better agreement with results for white dwarfs (70%) (cf. Weidemann, 1987).