Abundances in planetary nebulae: NGC 6886

Abstract

ISO and IUE spectra of the round-shaped planetary nebula NGC 6886 are combined with spectra in the visual wavelength region taken from the literature to obtain a complete, extinction corrected spectrum from ultraviolet to infrared wavelengths. The characteristics of the nebula and its central star are determined by various methods including photoionization modeling using Cloudy. The results of the modeling are checked against the observational data and compared to those derived from a more classical abundance determination approach. The abundances determined are found to differ substantially from earlier results although the observations used are essentially the same, except for the inclusion of the ISO results. The reasons for this difference are discussed. Finally, the main results are interpreted in terms of the evolutionary stage of NGC 6886 and its central star.