ON THE ORIGINS OF ORGANIC-MATTER IN CARBONACEOUS CHONDRITES

Carbonaceous chondrites, a sub-class of meteorites contain organic mat ter. This organic matter is a very complex mixture of various kinds of organic molecules together with a highly unsaturated polymer called k erogen. The origins of this organic matter remain a subject of active research. In the work described here, we focused our attention on vola tile hydrocarbons. Ratios of heavy to light stable isotopes of carbon and hydrogen are known for this class of molecules. Comparisons betwee n these values and the corresponding values obtained for samples resul ting from Fischer-Tropsch-Type synthesis provide information about the origin of volatile hydrocarbons. The presolar origin is certainly a p lausible scenario but the FTT synthesis remains a possibility.