Electron density measurements in NGC 6720.
1976; IOP Publishing; Volume: 205; Linguagem: Inglês
10.1086/154335
ISSN1538-4357
AutoresL. H. Aller, Harland W. Epps, S. J. Czyzak,
Tópico(s)Astronomical Observations and Instrumentation
Resumoview Abstract Citations (12) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Electron density measurements in NGC 6720. Aller, L. H. ; Epps, H. W. ; Czyzak, S. J. Abstract Spectral scans of NGC 6720 obtained with the Robinson-Wampler image-tube scanner on the Lick 3.0 m reflector have been analyzed to obtain electron temperatures from the [N ii] AA5755/6584 ratio and electron densities from the [S ii] AA6717/6731 and [Cl iii] AA55l7/5537 ratios. Comparison of these data with those obtained by previous observers for [0 ii], [0 iii], and [S ii] support the following model: The [S ii], [Cl iii], and presumably also the [N ii] radiation originates in filaments somewhat denser and cooler than the [0 ii] emitting region, while the [0 iii] radiation comes primarily from interior zones that are at least 1000 K hotter than the [N ii] emitting regions. It also suggests that the [N ii] and [S ii] emission observed near the center of the nebula is produced by outer shell material seen in projection. Subject headings: nebulae: individual - nebulae: planetary Publication: The Astrophysical Journal Pub Date: May 1976 DOI: 10.1086/154335 Bibcode: 1976ApJ...205..798A full text sources ADS | data products SIMBAD (1)
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