Quantitative Spectroscopy of the Aurora. I. The Spectrum of Bright Aurora between 7000 and 9000 Å at 7.5 Å Resolution

Abstract

Averaged spectra of bright aurora [Formula: see text] in the wavelength range 7000–9000 Å with a resolution of 7.5 Å are presented. These spectra, divided into four 500 Å intervals, were obtained by averaging about 20 separate 12 s scans in each region. Intensity fluctuations during the scans were corrected by normalizing the spectrometer output by means of the signal from a λ5577 photometer covering the same field of view. The spectra, corrected for atmospheric scattering and spectrometer sensitivity, were matched with synthetic spectra of the N2 first positive, [Formula: see text] Meinel, [Formula: see text] first negative, O2 atmospheric, and OH vibration–rotation bands so as to give values of the relative intensities of the bands and atomic lines within each 500 Å region. The resulting intensities have been tabulated after having been normalized approximately to IBC3 aurora. The synthetic spectrum (together with known atomic lines) provides a very good match to the observed spectrum except at several wavelengths where weak unidentified features seem to be present.