Formation, Alteration and Delivery of Exogenous High Molecular Weight Organic Compounds: Objectives of the Tanpopo Mission from the Point of View of Chemical Evolution

A wide variety of organic compounds have been detected in such extraterrestrial bodies as carbonaceous chondrites and comets. Amino acids have been confirmed in extracts from carbonaceous chondrites and cometary dusts. It was suggested that these organics were formed in quite cold environments. We irradiated possible interstellar media, such as a frozen mixture of methanol, ammonia and water, with high-energy particles. Amino acid precursors with high molecular weights were detected in the irradiated products. Such complex amino acid precursors are much more stable than free amino acids against radiation, and heat. It is suggested that IDPs brought much more organics than meteorites and comets. However, characteristics of organic compounds in IDPs are little known, since they have been collected only in terrestrial biosphere. We are planning the Tanpopo Mission, where IDPs would be collected in aerogel equipped on the Exposure Facility of the International Space Station. In addition, amino acids and their relating compounds would be exposed to space environments to see their possible alteration processes.

[1]  Y. Utsumi,et al.  Synthesis of amino acid precursors from simulated interstellar media by high‐energy particles or photons , 2008 .

[2]  Andrew Steele,et al.  Organics Captured from Comet 81P/Wild 2 by the Stardust Spacecraft , 2006, Science.

[3]  Michael E. Zolensky,et al.  Organic Globules in the Tagish Lake Meteorite: Remnants of the Protosolar Disk , 2006, Science.

[4]  Kensei Kobayashi,et al.  Experimental verification of photostability for free- and bound-amino acids exposed to γ-rays and UV irradiation , 2004 .

[5]  Yoshiro Furukawa,et al.  PRODUCTION OF β-AMINO ACIDS , 1999 .

[6]  S. Pizzarello,et al.  Enantiomeric Excesses in Meteoritic Amino Acids , 1997, Science.

[7]  J. van Paradijs,et al.  Interstellar dust, chirality, comets and the origins of life: Life from dead stars? , 1995 .

[8]  Carl Sagan,et al.  Endogenous production, exogenous delivery and impact-shock synthesis of organic molecules: an inventory for the origins of life , 1992, Nature.

[9]  F. R. Krueger,et al.  The organic component in dust from comet Halley as measured by the PUMA mass spectrometer on board Vega 1 , 1987, Nature.

[10]  J. Oró,et al.  Synthesis of adenine from ammonium cyanide , 1960 .

[11]  S. Miller.  A production of amino acids under possible primitive earth conditions. , 1953, Science.

[12]  James F. Kasting,et al.  Bolide impacts and the oxidation state of carbon in the Earth's early atmosphere , 2005, Origins of life and evolution of the biosphere.

[13]  Y. Takano,et al.  Possible cometary organic compounds as sources of planetary biospheres , 2002 .

[14]  J Koike,et al.  Formation of amino acid precursors in cometary ice environments by cosmic radiation. , 1995, Advances in space research : the official journal of the Committee on Space Research.

[15]  S. L. Miller,et al.  The mechanism of synthesis of amino acids by electric discharges. , 1957, Biochimica et biophysica acta.