"Websites report that Saturn's diameter is 119,871 km, Does this area include the rings too? "
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Investigating the Formation, Stability and Enantiomeric Ratios of Non-Protein Amino Acids in Low-Temperature Condensed-Phase Reactions
PI: Marla Moore
Understanding the origin and stability of complex organic molecules found in the interstellar medium and in solar system bodies is important since some of these objects may have played a role in the origin of life. In the particular case of the Murchison CM meteorite, over eighty amino acids have been reported, including both protein and non-protein types, but their origin is unknown. Furthermore, in CM chondrites the non-protein amino acids isovaline and aminoisobutyric (AIB) acid stand out as having a high abundance relative to glycine. In addition, an enantiomeric excess for L-isovaline has also been reported for Murchison, Murray, and LEW 90500 meteorites. To address these observations, a laboratory investigation into the formation of non-protein amino acids is proposed. The focus of the work will be amino-acid formation and enantiomeric ratios in the residues of interstellar- and cometary-type ices exposed to cosmic radiation. Laboratory analogs of interstellar and cometary ices will be ion-irradiated, and their infrared (IR) spectra recorded to monitor amino-acid formation and to uncover IR features of precursor molecules. Residues from irradiated ices, both hydrolyzed and unhydrolyzed, will be examined with LC-ToF-MS methods to check for amino-acid syntheses and determine enantiomeric ratios. Residues from preliminary studies of processed CO2 + (non-optically-active) butylamine ices show an apparent L-isovaline excess. To understand this apparent excess, and the one reported in meteorites, we will seek the identity of a possible co-eluting amino acid isomer, since it is extremely unlikely that the apparent excess is a real one. Understanding the chemical routes to non-protein amino acids will require isotopically-labeled reactants and the assembly of a library of reference chromatograms of relevant isomers for the chemical analyses. We will compare the results of our experiments with relevant analyses of meteoritic samples, and connections will be fully explored.
