The ionization structure of planetary nebulae. VII. New observations of the Ring Nebula
1987; IOP Publishing; Volume: 322; Linguagem: Inglês
10.1086/165787
ISSN1538-4357
Autores Tópico(s)Astronomy and Astrophysical Research
Resumoview Abstract Citations (28) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Ionization Structure of Planetary Nebulae. VII. New Observations of the Ring Nebula Barker, Timothy Abstract 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 Oand Balmer continuum electron temperatures agree well on the average and, like the Nelectron 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 Cabundance 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. Publication: The Astrophysical Journal Pub Date: November 1987 DOI: 10.1086/165787 Bibcode: 1987ApJ...322..922B Keywords: Emission Spectra; Ionization; Line Spectra; Observation; Planetary Nebulae; Abundance; Atomic Excitations; Spectrophotometers; Stellar Composition; Astrophysics; NEBULAE: ABUNDANCES; NEBULAE: INDIVIDUAL MESSIER NUMBER: M57; NEBULAE: INDIVIDUAL NGC NUMBER: NGC 6720; NEBULAE: PLANETARY; ULTRAVIOLET: SPECTRA full text sources ADS | data products SIMBAD (5) MAST (1) INES (1) Related Materials (16) Part 1: 1980ApJ...240...99B Part 2: 1982ApJ...253..167B Part 3: 1982ispn.rept.....B Part 4: 1983ApJ...267..630B Part 5: 1983ispn.rept.....B Part 6: 1984ApJ...284..589B Part 7: 1985ispn.rept.....B Part 8: 1985ApJ...294..193B Part 9: 1986ApJ...308..314B Part 10: 1986STIN...8717582B Part 12: 1987ispn.rept.....B Part 13: 1988ApJ...326..164B Part 14: 1988ispn.rept.....B Part 15: 1989ApJ...340..921B Part 16: 1989STIN...9029274B Part 17: 1991ApJ...371..217B
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