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Session 97 - Planetary Nebulae.
Display session, Thursday, January 16
We present an abundance analysis, utilizing recombination theory, for the [WC] Wolf-Rayet central stars of the planetary nebulae NGC 6751, NGC 6905, NGC 5189 and for Sand 3. The [WC] stars are a hydrogen-deficient sub-group of the central stars of planetary nebulae. Their spectra exhibit strong, broad emission line features, indicative of stellar winds similar to those found in the Population I WC and WO stars. This analysis is based on optical spectrophotometry and IUE archive spectra of a sample of [WC] stars which show a strong OVI 3811,34 Å\/ feature in emission. We have performed a recombination line analysis of stellar wind emission lines which are judged to be optically thin, in order to derive relative carbon, oxygen and helium abundances. We also present a comparison of the derived wind abundances with those of the Population I WO stars, and with the late-type [WC] stars.
Program listing for Thursday