FORMATION OF ORGANIC-COMPOUNDS IN SIMULATED INTERSTELLAR MEDIA WITH HIGH-ENERGY PARTICLES

Abiotic formation of amino acid precursors in interstellar dusts (ISDs ) by cosmic radiation was quantitatively examined. In order to study t he formation of organic compounds in ISDs, ice mixtures of carbon mono xide (or methane), ammonia, and water made in a cryostat at 10 K were irradiated with high energy protons. Irradiated ice products were warm ed up to room temperature, while sublimed gases were analyzed with a q uadrupole mass spectrometer. Some hydrocarbons and alcohols were detec ted. Amino acid precursors, which gave amino acids after acid-hydrolys is, were detected in non-volatile products remaining on the substrate at room temperature. G-values of glycine precursors from methanol, amm onia, and water in solid state irradiation were about 6x10(-4), which was about two orders less than those in gasous state irradiation. The present results suggest that a considerable amount of organic compound s formed in extraterrestrial environments were supplied to the primiti ve earth before the origin of life.