MULTICYCLE FLUORESCENCE - APPLICATION TO S2 IN COMET IRAS-ARAKI-ALCOCK 1983VII

Fluorescence calculations have been made to analyze the B-X system of S2 which appeared in IUE spectra of Comet IRAS-Araki-Alcock 1983VII. Single- and multiple-cycle fluorescence calculations indicate that fluorescent equilibrium accounts for the observed S2 spectra despite the fact that the S2 lifetime against solar ultraviolet radiation is relatively short. This analysis confirms that emission peaks in the 3000-4000 Å range of ground-based spectra are due to the B-X bands of S2. The fluorescence calculation indicates that the previous S2 production rates should be reduced at least a factor of two. We also argue that collisional effects on the S2 spectra by neutrals, electrons, and ions are negligible compared with the effects of pure fluorescence. © 1990.