NON-RACEMIC AMINO ACID PRODUCTION BY ULTRAVIOLET IRRADIATION OF ACHIRAL INTERSTELLAR ICE ANALOGS WITH CIRCULARLY POLARIZED LIGHT
- Univ Paris-Sud, 'Astrochimie et Origines', Institut d'Astrophysique Spatiale, UMR 8617, F-91405 Orsay (France)
- Laboratoire de Chimie des Molecules Bioactives et des Aromes, UMR 6001, Universite de Nice-Sophia Antipolis, F-06108 Nice (France)
- Synchrotron SOLEIL, F-91192 Gif-sur-Yvette (France)
The delivery of organic matter to the primitive Earth via comets and meteorites has long been hypothesized to be an important source for prebiotic compounds such as amino acids or their chemical precursors that contributed to the development of prebiotic chemistry leading, on Earth, to the emergence of life. Photochemistry of inter/circumstellar ices around protostellar objects is a potential process leading to complex organic species, although difficult to establish from limited infrared observations only. Here we report the first abiotic cosmic ice simulation experiments that produce species with enantiomeric excesses (e.e.'s). Circularly polarized ultraviolet light (UV-CPL) from a synchrotron source induces asymmetric photochemistry on initially achiral inter/circumstellar ice analogs. Enantioselective multidimensional gas chromatography measurements show significant e.e.'s of up to 1.34% for ({sup 13}C)-alanine, for which the signs and absolute values are related to the helicity and number of CPL photons per deposited molecule. This result, directly comparable with some L excesses measured in meteorites, supports a scenario in which exogenous delivery of organics displaying a slight L excess, produced in an extraterrestrial environment by an asymmetric astrophysical process, is at the origin of biomolecular asymmetry on Earth. As a consequence, a fraction of the meteoritic organic material consisting of non-racemic compounds may well have been formed outside the solar system. Finally, following this hypothesis, we support the idea that the protosolar nebula has indeed been formed in a region of massive star formation, regions where UV-CPL of the same helicity is actually observed over large spatial areas.
- OSTI ID:
- 21560550
- Journal Information:
- Astrophysical Journal Letters, Vol. 727, Issue 2; Other Information: DOI: 10.1088/2041-8205/727/2/L27; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ALANINES
AMINO ACIDS
CARBON 13
GAS CHROMATOGRAPHY
HELICITY
METEORITES
NEBULAE
SOLAR SYSTEM
ULTRAVIOLET RADIATION
CARBON ISOTOPES
CARBOXYLIC ACIDS
CHROMATOGRAPHY
ELECTROMAGNETIC RADIATION
EVEN-ODD NUCLEI
ISOTOPES
LIGHT NUCLEI
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PARTICLE PROPERTIES
RADIATIONS
SEPARATION PROCESSES
STABLE ISOTOPES