Faint Emission Lines in the Blue and Red Spectral Regions of the Night Airglow11Lick Observatory Bulletin 1391. Based on observations obtained at the W. M. Keck Observatory, which is operated by the California Institute of Technology and the University of California.

Abstract

ABSTRACTCo‐added night‐sky spectra, obtained as by‐products of exposures with the Keck I 10 m telescope on Mauna Kea and the HIRES high‐resolution echelle spectrograph over a period of approximately 4 years, all completely independent of similar data published earlier, are presented. The new data total over 150 hours exposure in one order (5505–5625 Å), more than 100 hours in 16 orders, and more than 50 hours in all orders in the spectral range 3923–7853 Å and include smaller numbers of hours over the entire range 3618–9023 Å. From these data, co‐added in the red region to the previously published data, two additional Meinel OH bands, 8–1 and 7–0, were found in emission in the spectrum of the night airglow, the presence of the 6–0 band was confirmed, and numerous lines of the 10–4 and 10–5 bands were detected. Three Hg i light‐pollution lines were detected as weakly present in the Mauna Kea night sky. Three other predicted Meinel bands are too faint and still were not detected with certainty. Similarly, neither OD nor the Rbi or Cs i resonance lines were seen. Upper limits were set on the latter, which are consistent with their abundance ratios to K and the observed strength of the K i resonance line λ7699, if the excitation mechanisms of all these three alkali atoms were equally effective. Brief references are given to other papers in press based on these new spectral data and to other work in progress on identifications of many additional O2 bands in the spectrum of the night airglow. A table summarizes all the identifications of all OH emission bands in the spectrum of the night airglow, in all spectral regions.