open access

https://hdl.handle.net/2115/34708

Formation and Alteration of Complex Organic Compounds in Interstellar Space

日本語

2008-03-31

北海道大学低温科学研究所

Low Temperature Science

66

39-46

1章 分子雲における氷と低温化学過程

Complex organic compounds were detected in carbonaceous chondrites and comets, and their relevance to origins of life has been discussed. It was suggested that these extraterrestrial organics were originally formed in ice mantles of interstellar dusts (ISDs) in molecular clouds. It was reported that amino acid precursors were formed from ice mixtures simulating ISD ice mantles by irradiation with UV or high-energy particles, but the nature of the precursors before hydrolysis were unknown. We irradiated a frozen mixture of possible interstellar molecules (methanol, ammonia and water) with high-energy heavy ions. The products were complex precursors of amino acids with large molecular weights. Such “complex amino acid precursors” were much more stable than free amino acids against irradiation with γ-rays or heavy ions. Irradiation of simulated interstellar complex organics with circular polarized light gave an enantiomeric excess of amino acid. These results suggested that formation of complex organics-bound amino acids and seeds of homochirality of amino acids were originally formed in interstellar cold environments. We propose a novel scenario of chemical evolution from interstellar organics to the first life on the Earth.

紀要論文

Version of Record

1880-7593