Measurements of the Singly Ionized Oxygen Auroral Doublet Lines lambdalambda7320, 7330 Using High-Resolution Sky Spectra

• Published in: The Astrophysical journal 2004-05, Vol.606 (1), p.605-610
• Main Authors: Sharpee, Brian D, Slanger, Tom G, Huestis, David L, Cosby, Philip C
• Format: Article
• Language: English
• ISSN: 0004-637X; 1538-4357

The wavelengths of the individual [O II] 2s super(2)2p super(3) super(2)D[image]-2s super(2)2p super(3) super(2)P[image] lambda7320 and [O II] 2s super(2)2p super(3) super(2)D[image]-2s super(2)2p super(3) super(2)P[image] lambda7330 auroral doublet component lines have been measured directly in the nightglow for the first time, from high-resolution spectra obtained with the High Resolution Echelle Spectrophotometer (HIRES) spectrograph on the Keck I telescope at the W. M. Keck Observatory. Specifically, we find doublet splittings of 1.077 plus or minus 0.003 Aa and 1.080 plus or minus 0.003 Aa at lambda7320 and lambda7330, respectively, with the former significantly larger than the often quoted and utilized value of 0.8 Aa from Moore and in line with the National Institute of Standards and Technology (NIST) (1.07 Aa) as well as more recent astrophysical observations of the lines in planetary nebulae, including 1.07 Aa from de Robertis, Osterbrock, & McKee and 1.09 Aa from Barnett & McKeith. Our results suggest, however, that adjustments of +0.124 Aa and +0.131 Aa should be made to current NIST wavelengths for the blue and red components of the lambda7320 doublet respectively, while our wavelengths of the lambda7330 doublet components are little changed from current NIST values. The observed intensity ratio of lambda7320/lambda7330 from these measurements agrees with the theoretical value calculated under conditions of thermally populated super(2)P super(o) levels.