Summary: | On the basis of chemical kinetic consideration, we examine processing of carbon and nitrogen compounds that leads to the linear relation between the logarithmic contents of C and N in carbonaceous chondrites: log N=a log C-b, found by A. Shimoyama et al. (Chem. Lett., 10, 2013, 1987), where a>1 and b are constants. It is shown that the linear relation results from dissociation of organic polymer in the grains before accretion to parent body-sized objects by radiation that penetrates through the grains such as cosmic ray. Condensation of volatile molecules composed of C and N is also examined as a possible process to form precursors of organic compounds in carbonaceous chondrites. From an analysis of a model thermodynamic system, it is conjectured that this process can also realize the linear relation under certain conditions. Fourteenth Symposium on Antarctic Meteorites. 6-8 June 1989. National Institute of Polar Research, Tokyo, Japan.
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