The evolution of polycyclic aromatic hydrocarbons under simulated inner asteroid conditions

Abstract

Abstract Large polycyclic aromatic hydrocarbons ( PAH s) are an important component of the interstellar medium. PAH s have been identified in the soluble and insoluble matter of carbonaceous chondrites ( CC s). Here, we study the evolution of PAH s under conditions relevant to the interiors of asteroids and compare our results to PAH s observed in CC s. We have performed long‐term and short‐term hydrothermal experiments, in which we exposed PAH ‐mineral mixture analogs of meteorites to temperature conditions representative of those predicted for asteroids interiors. Our results show that small PAH s with melting points within the aqueous alteration temperature of CC s form carbonaceous spherules in the presence of water. In this work, we describe the microstructure and morphology of these spherules. We discuss the similarities and differences compared to globules isolated from CC s.