The Abundance of Oxygen in the Planetary Nebula NGC 7027
Open Access
- 1 July 1960
- journal article
- Published by Oxford University Press (OUP) in Monthly Notices of the Royal Astronomical Society
- Vol. 121 (1) , 76-96
- https://doi.org/10.1093/mnras/121.1.76
Abstract
The abundances of O 0 , O + and O +2 are determined from [O I ], [O II ] and [O III ] forbidden lines and the abundances of O +3 , O +4 and O +5 from O III , O IV and O V recombination lines. In the recombination calculations cascade from all upper levels is taken into account. It is found that O +3 is the most abundant oxygen ion and that the abundance of O +5 is small. The chemical abundance ratio is found to be N (O)/ N (H) = 1.2 × 10 −3 .Keywords
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