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P. Coll, J.-M. Bernard, F. Raulin (LISA)
A wide range of experiments have already been carried out (Thompson et al, 1991; McDonald et al, 1994; de Vanssay et al, 1995; McKay, 1996; Coll et al, 1997, 1998a,b; and other Refs.) to mimic the chemical evolution of Titan's atmosphere, by irradiating gas mixtures of N2 and CH4 with different energy sources. All the organics already observed in the gas phase in Titan's atmosphere have been detected in such simulation experiments. Furthermore, many others are produced which could also be present on Titan. Until very recently, only one organics remained detected in Titan and not in laboratory simulation : C4N2. A full program of experimental research has been developed at LISA, which was able to provide a complete identification of a wide range of compounds, proposed to be present in Titan's atmosphere, including C4N2. We will present here the results of another investigation carried out with the same experimental device, to more specifically study the chemistry of Titan's O-containing compounds. Discovered on Titan, CO, H2O and CO2 (due to external sources and possible internal sources) can induce the production of several oxygenated compounds through solar ultraviolet radiation, Saturn magnetospheric particles and galactic cosmic rays. The formation of O-containing compounds was taken into account by several models of chemistry (as Toublanc et al., 1995), but the results they proposed were not faced to simulation experiments. After presenting a short statement of theoretical prevision, we will emphasize the new and quite unexpected results we have obtained.
This work is mainly supported by grants from CNES, The French Space Agency.
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The author(s) of this abstract have provided an email address for comments about the abstract: pcoll@lisa.univ-paris12.fr