Formation of Amino Acid Precursors and Caboxylic Acid in Slightly Reducing Primitive Atmospheres by Cosmic rays and Solar Energetic Particles

Abstract

In order to examine possible formation of organics in slightly reducing primitive atmospheres, mixtures of N₂，CH₄，CO₂ and H₂O were irradiated with high-energy protons or UV light, or were subjected to spark discharges, and amino acids and carboxylic acids in the products were determined. While UV and spark discharges did not yielded amino acids if the molar ratio of CH4 was less than 10%, amino acid precursors gave amino acids even if it was as low as 0.5%. Carboxylic acids were formed by spark discharges or proton irradiation even when no methane was added. It has been reported that young solar-type stars occur superflares. It was suggested that major energy sources for production of amino acids in the primitive Earth atmosphere was extraterrestrial high-energy particles such as galactic cosmic rays and/or solar energetic particles.