Meteorite Parent Body Aqueous Alteration Simulations of Interstellar Residue Analogs

TL;DR

This study simulates aqueous alteration of interstellar residue analogs to understand the formation and evolution of prebiotic organics in meteorite parent bodies, revealing how processing influences organic distributions relevant to the origin of life.

Contribution

It provides the first experimental simulation of interstellar organic alteration under meteorite parent body conditions, linking interstellar chemistry to meteoritic organics.

Findings

Abundance trends of amino acids remain consistent pre- and post-aqueous alteration.

Aqueous processing causes about 2-fold variation in amino acid abundances.

Higher levels of volatile amines suggest efficient transfer of interstellar organics to solar system bodies.

Abstract

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 > \b{eta}-alanine does not change from pre- to post-aqueous alteration, suggesting that certain 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 {\deg}C, and the changes in the {\alpha}- to \b{eta}-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 \b{eta}-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 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.