Trace of planetary nebula evolution by distance-independent parameters

Abstract

Using existing infrared and radio data on a sample of 432 planetary nebulae, we derived a number of distance-independent parameters for comparison with evolutionary models of planetary nebulae. We find that many of the observed properties of planetary nebulae can be explained by current central star evolutionary models, even if the time scales are subject to significant change by a factor of up to an order of magnitude. Specifically, we find that the evolutionary tracks are well separated in the radio surface brightness-central star temperature plane, therefore allowing us to determine the core mass of individual planetary nebulae. We also obtain the luminosity and gravity of the central stars of individual nebulae, from their temperature and core mass, without relying on the distance assumptions. We find that our results of the core mass are in good agreement with those of Mendez et al. (1992) and Tylenda et al. (1991). A systematic, large discrepancy is found between the luminosity found in this work and that found by Gathier and Pottasch (1986).