Energetics of Amino Acid Formation in weakly reducing planetary atmospheres: Titan and Primitive Earth

Abstract

In order to examine possible formation of organic compounds in weakly-reducing atmospheres, mixtures of CO₂, CH₄, N₂ and H₂O (simulated primitive Earth atmosphere) were irradiated with high energy protons, or were subjected to spark discharges. Also, a mixture of CH₄ and N₂ (simulated Titan atmosphere) was irradiated with high-energy protons or gamma rays. In the case of spark discharges, amino acids were not detected when molar ratio of methane was less than 30 %, but proton irradiation gave amino acids even molar ratio of methane was 1%. Simulated Titan atmosphere also gave amino acids by proton irradiation. These results suggested that cosmic rays are an important energy sources for amino acid production in weakly reducing atmospheres.