Meteorite Parent Body Aqueous Alteration Simulations of Interstellar Residue Analogs

Some families of carbonaceous chondrites are rich in prebiotic organics that may have contributed to the origin of life on Earth and elsewhere. However, the formation and chemical evolution of complex soluble organic molecules from interstellar precursors under relevant parent body conditions has not been thoroughly investigated. In this study, we approach this topic by simulating meteorite parent body aqueous alteration of interstellar residue analogs. The distributions of amines and amino acids are qualitatively and quantitatively investigated and linked to closing the gap between interstellar and meteoritic prebiotic organic abundances. We find that the abundance trend of methylamine > ethylamine> glycine > serine > alanine > beta-alanine does not change from pre- to post-aqueous alteration, suggesting that certain parental cloud conditions have an influential role on the distributions of interstellar-inherited meteoritic organics. However, the abundances for most of the amines and amino acids studied here varied by about 2-fold when aqueously processed for 7 days at 125 degrees C, and the changes in the alpha- to beta-alanine ratio were consistent with those of aqueously altered carbonaceous chondrites, pointing to an influential role of meteorite parent body processing on the distributions of interstellar-inherited meteoritic organics. We detected higher abundances of alpha- over beta-alanine, which is opposite to what is typically observed in aqueously altered carbonaceous chondrites; these results may be explained by at least the lack of minerals, inorganic species, and insoluble organic matter-relevant materials in the experiments. The high abundance of volatile amines in the non-aqueously altered samples suggests that these types of interstellar volatiles can be efficiently transferred to asteroids and comets, supporting the idea of the presence of interstellar organics in solar system objects.

Automated summary

Some carbonaceous chondrites contain prebiotic organics that may have played a role in the origin of life. This study investigates the formation and evolution of complex organic molecules under meteorite parent body conditions. The abundance of certain amines and amino acids remains consistent before and after aqueous alteration, suggesting the influence of parental cloud conditions. However, most of the studied amines and amino acids show varying abundances after aqueous processing, indicating the influence of meteorite parent body processing. The presence of interstellar organics in solar system objects is supported by the efficient transfer of volatile amines.