A spectroscopic survey of 51 planetary nebulae

Abstract

Line intensity data obtained with an image-tube scanner at the 3 m Lick telescope are used to obtain plasma diagnostics and ionic concentrations. With the aid of theoretical models the authors obtain ionization correction factors and find chemical abundances. Abundance patterns of C, N, and O show considerable spread owing to differing nuclear processing rates in progenitor stars. Most objects show enhanced C or N, suggesting that nucleosynthesis products have been mixed with stellar surface layers.