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C. Reylé (Observatoire de Besançon), D.C. Boice (SwRI)
High-resolution spectra of comets Hyakutake and Hale-Bopp provide a unique opportunity to advance our knowledge of parent species in comets. To interpret these observations, a detailed model that combines time-dependent fluorescence calculations with a global coma model based on gas dynamics and chemistry has been developed. Due to the short lifetime of S2, it is concentrated in the innermost region of the coma where dynamics and chemistry are most important. S2 was first discovered in Comet Iras-Araki-Alcock in 1983 and also in Comet Hyakutake in 1996. Using this versatile model, a systematic study of the vibrational-rotational spectrum of S2 is undertaken, including relevant effects, such as, non-equilibrium state superposition, the Swings effect, and the number density profile within the coma due to dynamics and chemistry. Synthetic fluorescence spectra of S2 are calculated as a function of time after release from the nucleus to investigate the importance of the above effects on the scale length and abundance of S2 in comets.
Support for this work was provided by NSF and the visiting researcher program of the Université de Franche-Comté.
The author(s) of this abstract have provided an email address for comments about the abstract: celine@obs-besancon.fr