A New Search for Amino Acid Precursors on Icy Solar System Objects with Improved Spectroscopic Parameters

Southwest Research Institute, San Antonio TX

Investigators

Abstract

0085614 Young Amino acid precursors (AAPs) have been detected on meteorites, in comets, and in the interstellar medium (ISM). In addition, these precursors (HCN, NH 3 , and CH 3 OH) have been irradiated with UV photons in a 10 K water ice matrix to form glycine without any aqueous chemistry taking place. Dr. Eliot Young at the Southwest Research Institute will lead a project that will conduct a survey on 16 of the icy bodies in the solar system to look for AAPs. The goal is to assess the distribution of AAPs throughout the icy bodies of the solar system and determine under what conditions AAPs can survive and participate in prebiotic chemistry. Dr. Young expects that this telescopic survey will be more sensitive to the presence of AAPs than any previous survey. The research team's efforts are concentrated in three areas: 1. Observations at 3 - 5 Mm using NIRSPEC. The 3 - 5 Mm spectral range contains the fundamental transitions of the AAPs. These are an order of magnitude stronger than the overtone transitions which have been customarily observed. The breakthrough is NIRSPEC, a 1 - 5 Mm spectrograph on the Keck telescope on Mauna Kea, Hawaii, that will acquire targets as faint as Charon. 2. New Optical Constants: Interpretation of spectral data requires accurate optical constants. The team will generate sample AAP ices under a variety of temperatures and in water and nitrogen host matrices. 3. More Accurate Spectral Modeling: Modifications to a current Hapke code based on the Monte Carlo results will be developed. This will allow more accurate fits to bright ices in which the scattering is non-isotropic and to cases in which the imaginary index is close to 1. This program of observations and analysis is expected to discover many new constituents throughout the solar system, including many molecules with prebiotic significance. Taken as a whole, the results of the survey will help us to understand the conditions in which AAPs can survive in surface ices. This project is funded through the Division of Astronomical Sciences for the NSF's Life in Extreme Environments program. ***