Solid State Molecular Reactors in Space

Abstract

Lunar minerals and impact glasses, convert the polyatomic beam of solar wind (SW) ions into a flux of small molecules ( e.g. , H 2 , N 2 , H 2 O, CO, CO 2 , CH 4 , C 2 H 4 , C 2 H 6 , HCN, metal carbides and deuterides, etc.). They thus behave as “Solid State Molecular Reactors”. Moreover,  ~100–200    μ m size micrometeoroids ( μ Ms) have also been exposed to the SW in the zodiacal cloud, before being captured by the Earth and recovered as Antarctic micrometeorites. They are mostly composed of a PAH-rich hydrous-carbonaceous material, which amplifies their power as molecular reactors. In particular, during the first  ~200 Myr of the post-lunar period, about 75% of the μ Ms have been melted and/or volatilized upon atmospheric entry. The release of their volatile species triggered a cosmic volcanism around the mesopause that ruled the formation of the early Earth’s atmosphere and climate. Furthermore, a fraction of the μ Ms that survive unmelted upon atmospheric entry did settle on the proto-oceans floors. Upon further burial in sediments their constituent PAH-rich kerogen was cracked into abiotic oil, which generated giant oil slicks that fed prebiotic chemistry. Many stars, of all ages and types, are embedded into a secondary debris-disk loaded with ion implanted μ Ms. Some of them are expelled to the interstellar medium (ISM) where they behave first as “dormant-invisible” molecular reactors, until they became reactivated by various processes to synthesize interstellar molecules. This short paper only focus on some highlights of this research dealing with the synthesis of important interstellar molecules, including the most abundant ones (H 2 and CO) and H 2 O, HCN and PAHs, all involved in prebiotic chemistry.