2008 Annual Science Report
NASA Ames Research Center Reporting | JUL 2007 – JUN 2008
Prebiotic Organics From Space
This project has three components, all aimed to better our understanding of the connection between chemistry in space and the origin of life on Earth and possibly other worlds. Our approach is to trace the formation and evolution of compounds in space, with particular emphasis on identifying those that are interesting from a prebiotic perspective, and understand their possible roles in the origin of life on habitable worlds. We do this by first measuring the spectra and chemistry of materials under simulated space conditions in the laboratory. We then use these results to interpret astronomical observations made with ground-based and orbiting telescopes. We also carry out experiments on simulated extraterrestrial materials to analyze extraterrestrial samples returned by NASA missions or that fall to Earth in as meteorites.
We have made substantial progress in all three focus areas this year.
(1) Conversion of our world unique collection of PAH mid-IR spectra (>800) into a database is nearly complete. This is the spectral collection upon which the interstellar PAH model is based. Database/web user interface should be ready for launch March, 2009 and will revolutionize how cosmic spectra are analyzed. Three PAH related papers were published, one on NIR spectra of N-containing PAHs; one on mid-IR spectroscopy of very large PAHs; and one on IR properties of PAH ions in water ice analogs of interstellar and Solar System ices.
(2) Several papers describing reactions during the production of prebiotic compounds by UV irradiation of cosmic ices appeared in MAPS and ApJ. One described isotopic experiments showing that the production of amino acids in astrophysical ices is complex and does not follow the pathways predicted by Strecker synthesis or radical interaction models. A review of prebiotic chemical evolution was published as part of the American Chemical Society’s series on Chemical Education.
(3) Mission involvement: Scott Sandford, CoI on Stardust and member of the sample allocation subcommittee, is intimately involved with extraction, distribution, and analysis of samples from Comet 81P/Wild 2. Results were published in the January/February 2008 issue of MAPS. Cometary organics are richer in oxygen and nitrogen than meteoritic organics and also contain volatile materials not observed in meteorites. Some organics are enriched in D and 15N, implying an interstellar/presolar chemical heritage. This work was recently reviewed in the first volume of AnnRev Analytical Chemistry.
The concept of a lander/rover deployable Organic Surveyor based on UV induced Luminescence has been finalized, the necessary equipment to start this has been purchased with our 2007 NAI DDF funds and the experimental apparatus is under construction. We have also just been awarded a second Astrobiology DDF grant (PI Ehrenfreund).
PROJECT INVESTIGATORS:Louis Allamandola
PROJECT MEMBERS:Charles Apel
RELATED OBJECTIVES:Objective 1.1
Models of formation and evolution of habitable planets
Outer Solar System exploration
Sources of prebiotic materials and catalysts
Origins of cellularity and protobiological systems
Effects of extraterrestrial events upon the biosphere
Biosignatures to be sought in Solar System materials
Biosignatures to be sought in nearby planetary systems