Solid State Molecular Reactors in Space

Abstract

Lunar minerals and impact glasses, convert the polyatomic beam of solar wind (SW) ionsinto a flux of small molecules (e.g., H₂, N₂,H₂O, CO, CO₂, CH₄, C₂H₄,C₂H₆, HCN, metal carbides and deuterides, etc.). They thus behaveas “Solid State Molecular Reactors”. Moreover,  ~100–200   μmsize micrometeoroids (μMs) have also been exposed to the SW in thezodiacal cloud, before being captured by the Earth and recovered as Antarcticmicrometeorites. 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 μMs havebeen melted and/or volatilized upon atmospheric entry. The release of their volatilespecies triggered a cosmic volcanism around the mesopause that ruled the formation of theearly Earth’s atmosphere and climate. Furthermore, a fraction of the μMsthat survive unmelted upon atmospheric entry did settle on the proto-oceans floors. Uponfurther burial in sediments their constituent PAH-rich kerogen was cracked into abioticoil, which generated giant oil slicks that fed prebiotic chemistry. Many stars, of allages and types, are embedded into a secondary debris-disk loaded with ion implantedμMs. Some of them are expelled to the interstellar medium (ISM) wherethey behave first as “dormant-invisible” molecular reactors, until they became reactivatedby various processes to synthesize interstellar molecules. This short paper only focus onsome highlights of this research dealing with the synthesis of important interstellarmolecules, including the most abundant ones (H₂ and CO) and H₂O, HCNand PAHs, all involved in prebiotic chemistry.