2010 Annual Science Report
NASA Ames Research Center Reporting | SEP 2009 – AUG 2010
Cosmic Distribution of Chemical Complexity
This project is aimed to improve our understanding of the connection between chemistry in space and the origin of life on Earth, and its possibility on other worlds. Our approach is to trace the formation and development of chemical complexity in space, with particular emphasis on understanding the evolution from simple to complex species. The work focuses upon molecular species that are interesting from a biogenic perspective and also upon understanding 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 meteorites.
(1) In August 2010, we put on the web our collection of more than 600 polycyclic aromatic hydrocarbon (PAH) spectra together with the tools needed to query the data and analyze astronomical spectra (Figure 1). Three PAH-related papers were published to support missions such as Spitzer, SOFIA, Herschel, and JWST. Two other papers were published that describe a detailed lab study of the photochemical kinetics of several PAHs in cosmic ice analogs, providing the first solid state reaction rates needed to model extraterrestrial ice chemistry from the Solar System to the ISM. This novel modeling capability opens a new field of study.
(2) We have published one paper and are working on others that describe the production of prebiotic compounds by UV irradiation of cosmic ices. The published paper appeared in Astrobiology and described work showing the photolysis of pyrimidine in H2O ices produces a host of new compounds, including the nucleobase uracil (Figure 2). A second paper in preparation shows that the addition of ammonia to the ice results in the production of the nucleobase cytosine.
(3) Mission involvement- Co-I Sandford continues to be involved with the extraction, distribution, and analysis of samples from Comet 81P/Wild 2 returned by the Stardust mission (two related papers in the last year). He also continues to work as a Co-I on the Hayabusa asteroid sample return mission, which returned samples to Earth in June 2010 and is now actively studying these samples (Figure 3). Andrew Mattioda is a member of the Science Team for the O/OREOS (Organisms/ORganics Exposure to Orbital Stresses), NASA’s first Astrobiology Small Payloads mission. He and Nathan Bramall are working on the SEVO (Space Environment Viability of Organics) component for O/OREOS.
This year Pascale Ehrenfreund (Wisconsin team), in collaboration with Co-Is Allamandola and Mattioda was awarded an NAI DDF grant to investigate the modification of organic materials (particularly PAHs) under interstellar conditions via UV-Visible spectroscopy. This DDF employs post-doctoral researcher Kathryn Bryson, who has set up the UV-Vis spectrometer system and has begun a spectroscopic study of thin films of astrobiologically interesting organic molecules.
PROJECT INVESTIGATORS:Louis Allamandola
PROJECT MEMBERS:Murthy Gudipati
RELATED OBJECTIVES:Objective 1.1
Formation and evolution of habitable planets.
Outer Solar System exploration
Sources of prebiotic materials and catalysts
Origins and evolution of functional biomolecules
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