O++ relative abundance in IC 418 from permitted lines

Abstract

Two multisite campaigns devoted to HD 35914, the variable central star of IC 418, have been performed (Handler et al., 1996). In the second one, many spectra of the star were obtained during five nights on November 1994. The Echelle REOSC spectrograph and a 1024 × 1024 Tektronix CCD detector, attached to the 2.1m telescope at the Observatorio Astronómico Nacional in San Pedro Mártir, México, was used then. The north-south diameter of the nebula was included in the 20 spectra taken the night of November 18 (184–minute total exposure). The spectral coverage and reciprocal resolution was 4300 å to 7350 å and about 0.16å/pix, respectively. The projected slit size was 1″ × 26″, approximately.