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[38.06] Measurements of the Singly Ionized Oxygen Auroral Doublet Lines \lambda\lambda7320,7330Å\ Using High Resolution Sky Spectra

D. L. Huestis, B. D. Sharpee, P. C. Cosby, T. G. Slanger (SRI)

The wavelengths of the individual [O II] 2s²2p^{3 2}D_5/2^o -- 2s²2p^{3 2}P_1/2,3/2^o \lambda7320Å\ and [O II] 2s²2p^{3 2}D_3/2^o -- 2s²2p^{3 2}P_1/2,3/2^o \lambda7330Å\ auroral doublet component lines have been measured directly in the nightglow for the first time, from high resolution spectra obtained with the HIRES spectrograph on the Keck I telescope at the W.M. Keck Observatory. Specifically, we find 7320Å\ and 7330Å\ doublet splittings of 1.077±0.003Å\ and 1.080±0.003Å\ respectively, significantly larger than the often quoted and utilized value of 0.8Å\ from Moore (1949, Atomic Energy Levels, Vol 1), and in line with NIST (1.07Å) as well as more recent astrophysical observations of the lines in planetary nebulae including 1.07Å\ from DeRobertis, Osterbrock, & McKee (1985,ApJ,293,459) and 1.09Å\ from Barnett & McKeith (1988,MNRAS,234,241). Our results suggest, however, that adjustments of +0.124Å\ and +0.131Å\ should be made to current NIST wavelengths for the blue and red components of the 7320Å\ doublet respectively, while the wavelengths of the 7330Å\ doublet components are little changed from current NIST values. The observed intensity ratio of 7320Å/7330Å\ from these measurements agrees with the theoretical value calculated under conditions of thermally populated ²P^o levels.

Supported by grants from NSF Aeronomy and NASA Office of Space Science.

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.