On the forbidden red lines of oxygen in comets

Eighteen spectra of 8 different comets observed at high and medium resolution were analyzed in the 627 to 637 nm region to determine the contributions of the (OI) red doublet and of the various NH2 lines present in this wavelength interval. Results confirm that there exist appreciable variations not only in the (OI)/NH2 ratio, but also in the relative intensities of the NH2 features among themselves, therefore, it is not justified to derive the (OI) line flux from the 630.0 blend, as was done in previous low-resolution work, by assuming a fixed relative strength of the NH2 emission contained in this blend. Mapping of these emissions over the coma is recommended.