A Detailed Analysis of the Stellar and Nebular IUE Spectrum of the Peculiar ``O VI Sequence'' Planetary Nebula NGC 40

Abstract

A detailed analysis of archival individual and co-added low- and high-dispersion IUE spectra of the planetary nebula NGC 40 has been performed, using NEWSIPS extracted spectra. More than 50 emission lines and numerous absorption features have been identified, and emission-line fluxes and equivalent widths were measured. Terminal wind velocities from P Cygni profiles and electron densities were redetermined. Several inconsistencies were found in earlier works for this peculiar low-excitation planetary that is excited by a 90,000 K ``O VI sequence'' WC8 star. The detection of Fe II lines that are resonantly excited by the O VI λ1031 line supports the O VI classification for the central star.