Origin of the hydrocarbon component of interplanetary dust particles

Abstract

Using experiments as a basis, we have developed a scenario for the origin of the hydrocarbon material of carbonaceous chondrites. This scenario can also serve as an explanation for the origin of the hydrocarbon component of interplanetary dust particles (IDPs). The formation of polycyclic aromatic hydrocarbon (PAH) molecules in the atmospheres of carbon stars undergoing a late stage of stellar evolution is indicated by the observed unidentified infrared (UIR) emission bands. Those molecules are then transported through interstellar space where they become enriched with deuterium through ion molecule reactions when passing through cold dark clouds. Many of those PAH molecules are subsequently hydrogenated and cracked in a hydrogen‐dominated plasma such as that which would have occurred in the solar nebula. The resulting mixture of alkanes and residual deuterium‐rich PAH molecules was then incorporated into the mineral fraction of the parent bodies of carbonaceous chondrites and IDPs.