Photo and thermochemistry of interstellar ices: from astrochemistry to astrobiology?

Louis D’endecourt

April 14, 2011

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Abstract: Ices are widespread in molecular clouds where they are observed by infrared astronomical spectroscopy. Laboratory simulations have helped in the past to identify these ices and deduce their mean chemical composition. Some observed bands reveal that energetic processing of interstellar ices is a well established fact. In the laboratory, UV irradiation of ices lead to the formation of complex organic residues that may provide prebiotic molecules. Debris of the primitive solar nebula (comets and then meteorites) do contain very similar molecules with the possibility to establish a link between interstellar chemistry, cosmochemistry within the solar nebula and prebiotic chemistry on the surface of a telluric planet, the Earth for instance. Recently, the production of left handed amino acid alanine in such experiments has allowed to propose a universal mechanism for the apparition of ‘homochirality’, a characteristic of living systems on Earth. Other molecules have been identified in such experiments that clearly suggest that the frontier between astrochemistry and astrobiology is about to be crossed.