title: Formation of bioorganic compounds in simulated planetary atmospheres by high energy particles or photons.
abstract: Various types of organic compounds have been detected in Jupiter, Titan, and cometary coma. It is probable that organic compounds were formed in primitive Earth and Mars atmospheres. Cosmic rays and solar UV are believed to be two major energy sources for organic formation in space. We examined energetics of organic formation in simulated planetary atmospheres. Gas mixtures including a C-source (carbon monoxide or methane) and a N-source (nitrogen or ammonia) was irradiated with the followings: High energy protons or electrons from accelerators, gamma-rays from 60Co, UV light from a deuterium lamp, and soft X-rays or UV light from an electron synchrotron. Amino acids were detected in the products of particles, gamma-rays and soft X-rays irradiation from each gas mixture examined. UV light gave, however, no amino acid precursors in the gas mixture of carbon monoxide, nitrogen and nitrogen. It gave only a trace of them in the gas mixture of carbon monoxide, ammonia and water or that of methane, nitrogen and water. Yield of amino acid precursors by photons greatly depended on their wavelength. These results suggest that nitrogen-containing organic compounds like amino acid precursors were formed chiefly with high energy particles, not UV photons, in Titan or primitive Earth/Mars atmospheres where ammonia is not available as a predominant N-source.
authors.affiliation: Department of Chemistry and Biotechnology, Yokohama National University, Hodogaya-ku, Yokohama 240-8501, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kobayashi
authors.forename: H
authors.initials: H
authors.lastname: Masuda
authors.forename: K I
authors.initials: KI
authors.lastname: Ushio
authors.forename: A
authors.initials: A
authors.lastname: Ohashi
authors.forename: H
authors.initials: H
authors.lastname: Yamanashi
authors.forename: T
authors.initials: T
authors.lastname: Kaneko
authors.forename: J I
authors.initials: JI
authors.lastname: Takahashi
authors.forename: T
authors.initials: T
authors.lastname: Hosokawa
authors.forename: H
authors.initials: H
authors.lastname: Hashimoto
authors.forename: T
authors.initials: T
authors.lastname: Saito
mesh_terms: D000409:Alanine / Q000138:chemical synthesis; D000596:Amino Acids / Q000138:chemical synthesis*; D000641:Ammonia / Q000737:chemistry; D001272:Atmosphere / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry / Q000528:radiation effects; D002248:Carbon Monoxide / Q000737:chemistry / Q000528:radiation effects; D018534:Earth, Planet; D019418:Evolution, Chemical; D019419:Evolution, Planetary; D005118:Extraterrestrial Environment / Q000737:chemistry*; D005998:Glycine / Q000138:chemical synthesis; D018535:Mars; D008697:Methane / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry / Q000528:radiation effects; D017785:Photons; D011522:Protons; D018539:Saturn; D017356:Synchrotrons; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D000596:Amino Acids; D011522:Protons; D014867:Water; D002245:Carbon Dioxide; D000641:Ammonia; D002248:Carbon Monoxide; D009584:Nitrogen; D000409:Alanine; D008697:Methane; D005998:Glycine