The Properties of Planetary Nebulae Nuclei: Stellar Winds

Abstract

We present IUE observations of some nuclei of Planetary Nebulae. From these data we derive the stellar photospheric parameters (Teff Lbol, log g), and the wind characteristics (velocity, mass loss rate). Teff, R∗, Lbol are derived from UV low resolution spectra, combining optical and radio data, from Bianchi (1988) or from new IUE data, with the same method (fit of the UV continuum with model atmospheres for high gravity stars, after correcting for reddening and for the contribution of continuum emission by the nebular gas). P Cygni profiles from IUE high resolution spectra are fitted with the SEI method and V∞ is derived. The non-LTE ionisation in the wind and the mass loss rate are computed as in Bianchi et al. (1986). Details are given in a forthcoming paper. The results for a first group of objects are given in the Table below.