The Ionization Structure of Planetary Nebulae. VI. NGC 7662

Abstract

Spectrophotometric observations of emission-line intensities over the spectral range 1400 - 7200 Å have been made in five positions in the planetary nebula NGC 7662. The variation of the Balmer decrement with position in the nebula suggests that there may be internal dust. The O⁺⁺ and Balmer continuum electron temperatures decrease with increasing distance from the central star. Standard equations used to correct for the existence of elements in other than the optically observable ionization stages give results that are consistent and in approximate agreement with abundances calculated using ultraviolet lines. The logarithmic abundances (relative to H = 12.00) are: He = 10.97, O = 8.63, N = 8.04, Ne = 7.96, C = 8.83, Ar = 6.18, and S = 6.62.