Abstract

We present first preliminary results from an exploratory spectral analysis of PG1159-035. An effective temperature of 120000 K (±20000 K) and a surface gravity of about log g=7 are derived from optical and ultraviolet profiles of carbon and helium lines. NLTE model atmospheres are used which are composed of H (1%), He (19%), C (40%) and O (40%, mass fractions). The abundances adopted are in accordance with predictions of stellar pulsation theory. A direct spectroscopic determination is under way. The analysis of optical CIV lines is rendered difficult due to the lack of a reliable line broadening theory which would have to account for a gradual change to broadening by linear Stark effect. Due to the complexity of the spectral analysis, reliable abundance ratios can only be derived from a systematic investigation employing a large grid of models.

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