Abstract
view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The composition of the Orion Nebula. Aller, Lawrence H. ; Liller, William Abstract Photoelectric spectrophotometric measurements of line intensities in the Orion Nebula are combined with Wyse's photographic measurements for the weaker lines to obtain the concentrations of various ions of the permanent gases. As noted by Osterbrock and others, there is evidence for large density fluctuations in this object. We have adopted a mean electron density NE = 4 X i~~ from the forbidden lines and TE = 90000K from the photoelectrically measured ~4363/ (N1 + N2) ratio. Approximate cross- sections have had to be used for sulfur, chlorine, and argon. A fairly well-defined empirical ionization curve was obtained. The following table compares the nebular abundances with those of early type stars as determined in the Michigan program: logN logN Star Nebula Star Nebula Nitrogen 9.2 9.1 Sulphur 9.0 9.1 Oxygen 10.0 10.0 Chlorine 8.7 7.3 Neon 10.1 10.2 Argon 8.4 8.6 University of Michigan Observatory, Ann Arbor, Mich. Publication: The Astronomical Journal Pub Date: 1959 DOI: 10.1086/108011 Bibcode: 1959AJ.....64R..49A full text sources ADS |
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