Ionization structure of planetary nebulae. Part 7: new observations in the ring nebula

Technical Report · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6581711

Barker, T

New optical spectrophotometric observations of emission-line intensities have been made in eight positions in the Ring Nebula corresponding to those observed previously with the Ultraviolet Explorer satellite; the total coverage is therefore 1400 to 7200 A. The intensities are in generally good agreement with those found previously in corresponding positions. The 0(++) and Balmer continuum electron temperatures agree well on the average and, like the N(+) electron temperatures, decrease with increasing distance from the central star. As found previously for the Ring Nebula and for other planetaries in this series, the lambda 4267 C 2 line intensity near the central star implies a C(++) abundance that is higher than that determined from the lambda 1906, 1909 C 3 lines. The discrepancy again decreases with increasing distance from the central star and vanishes from the outermost positions, again suggesting that the excitation mechanism from the lambda 4267 line is not understood. 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 appropriate agreement with abundances calculated using UV lines. The rather high abundances of O, N, and C, and, to some extent N, indicate that some mixing of CNO processed material into the nebular shell may have occurred in the Ring Nebula.

• Research Organization: Wheaton Coll., Norton, MA (USA)
• OSTI ID: 6581711
• Report Number(s): N-87-17582; NASA-CR-180141; NAS-1.26:180141
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
CARBON
DATA
ELEMENTS
EMISSION SPECTRA
EXPERIMENTAL DATA
INFORMATION
IONIZATION
MEASURING INSTRUMENTS
NEBULAE
NITROGEN
NONMETALS
NUMERICAL DATA
OXYGEN
PLANETARY NEBULAE
SPECTRA
SPECTROPHOTOMETERS