FORMATION OF CARBIDES AND HYDROCARBONS IN CHONDRITIC INTERPLANETARY DUST PARTICLES - A LABORATORY STUDY

The reaction between kamacite grains and H-2 + CO gas mixture has been tested in the laboratory under experimental conditions presumed for i nterplanetary dust particle (IDP) formation in a nebular-type environm ent (H-2:CO = 250:1; 5 x 10(-4) atm total pressure, and 473 K). Carbon deposition, hydrocarbon production in the C-1-C-4 range, and the form ation of an E-carbide phase occur when well-defined model FeNi bcc all oy (kamacite) particles are exposed to a mixture of H-2 + CO during 10 (3) h. These results strongly support the idea that gas-solid reaction s in the solar nebula during CO hydrogenation represent a plausible sc enario for the formation of carbides and carbonaceous materials in IDP s, as well as for the production of hydrocarbons through Fischer-Trops ch-type reactions.