Spectral Analysis of Central Stars of PNe Interacting with the Interstellar Medium

Abstract

Planetary Nebulae (PNe) are the result of heavy mass loss of the asymptotic giant branch (AGB) stars. They are understood in terms of Kwok's (1978) interacting-winds model as the product of the mass-loss history on the AGB and the central star (CS) evolution. Since the CS are close to the end of nuclear burning and at their hottest stage of evolution then, precise modeling of these pre-white dwarfs is a prerequisite in order to calculate reliable ionizing fluxes which are crucial input for the presently available 3D photoionization codes. In the framework of a systematic study of PNe which show evidence for an interaction with the ISM, we present a NLTE analysis of their CS.