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 interplanetary dust particle (IDP) formation in a nebular‐type environment (H 2 :CO = 250:1; 5 × 10 −4 atm total pressure, and 473 K). Carbon deposition, hydrocarbon production in the C 1 –C 4 range, and the formation of an ɛ‐carbide phase occur when well‐defined model FeNi bcc alloy (kamacite) particles are exposed to a mixture of H 2 + CO during 10 3 h. These results strongly support the idea that gas‐solid reactions in the solar nebula during CO hydrogenation represent a plausible scenario for the formation of carbides and carbonaceous materials in IDPs, as well as for the production of hydrocarbons through Fischer‐Tropsch‐type reactions.