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S.J. Kim (Kyunghee University)
When a comet approaches the sun, the nucleus continuously releases molecules. The released molecules are immediately exposed to solar radiation undergoing absorption and emission processes. Short-life molecules do not achieve flourescent equilibrium conditions during their lifetimes. Some long-life molecules also do not achieve steady states, if they have strict selection rules. Therefore, time-dependent fluorescence calculations are necessary to be considered in the analysis of cometary spectra. The lifetimes of CH, S2, and C2H6 are approximately 100, 500, and 100,000 seconds, respectively, at 1 AU from the sun. We will present the time-dependent fluorescence processes of the bands of these molecules and discuss the influence of the fluorescence calculations on the derivations of molecular abundances in comets.