2009 Annual Science Report

NASA Ames Research Center Reporting  |  JUL 2008 – AUG 2009

Cosmic Distribution of Chemical Complexity

Project Summary

This project seeks to improve 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 development of chemical complexity in space, with particular emphasis on understanding the evolution from simple to complex species focusing on those that are interesting from a biogenic perspective and also 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.

4 Institutions
3 Teams
16 Publications
0 Field Sites
Field Sites

Project Progress

Our unique collection of polycyclic aromatic hydrocarbon (PAH) spectra is now in database form. Tools to query the data and analyze astronomical spectra are being finalized for web launch. (Figure 1) This will revolutionize how astronomers analyze PAH spectra and understand how carbonaceous species evolve across the universe. We published five PAH-related papers, as follows: 1- Far-IR (Figure 2) and 1- 15 to 20 µm spectra of PAHs in preparation for Herschel and SOFIA. 2- on mid-IR spectroscopy of large PAHs. 1- on photochemistry of the PAH pyrene in water analogs of interstellar and Solar System ices. This last paper opens a new field of research.

We have published one paper and are working on several others describing reactions that produce prebiotic compounds by UV irradiation of cosmic ices. The paper published in Astrobiology described experiments showing that the photolysis of pyrimidine in H2O ices produces a host of new compounds, one of which is the nucleobase uracil (Figure 3). A second paper is in preparation showing that the addition of ammonia to the ice results in the production of the nucleobase cytosine.

One of us (Sandford) continues to be intimately involved with extraction, distribution, and analysis of samples from Comet 81P/Wild 2 returned by the Stardust mission (Figure 4). He is also continues to work as a CoI on the Hayabusa asteroid sample return mission, which is due back to Earth in June 2010. Another team member (Mattioda) is on the Science Team for the O/OREOS (Organisms/ORganics Exposure to Orbital Stresses), NASA’s first Astrobiology Small Payloads mission (Figure 5). He and Bramall are working on the SEVO (Space Environment Viability of Organics) component for O/OREOS.

This year Pascale Ehrenfreund, Wisconsin team, in collaboration with Louis Allamandola and Andrew Mattioda was awarded an NAI DDF grant to investigate the modification of organic materials under interstellar conditions via UV-Visible spectroscopy, particularly polycyclic aromatic hydrocarbons (PAHs). This DDF employs a post-doc Kathryn Bryson. This past year Kathryn has setup the UV-Vis spectrometer system and begun the collection of spectra for thin films of astrobiologically-relevant organic molecules.

Figure 1. The NASA Ames PAH IR spectral database. The yellow highlighted box summarizes the spectroscopic range covered and the variety of species in the database. The lower web 'screen shots’ are examples of the tools and capabilities of our web site.

Figure 2. Experimental (top) and theoretical (bottom) FIR spectra of coronene
(C24H12). The cross hatched areas in the experimental spectrum correspond to regions that are not accessible with the 12.5 μm mylar beam splitter. The molecular structures and arrows show the vibrational modes that give rise to the bands. The actual atom displacements are exaggerated by about a factor of 10.

Figure 3. The UV photolysis of pyrimidine in H2O ices results in the production of the nucleobase uracil.

Figure 4. Infrared absorbance maps for (a) CH2, (b) -CH3, and© C=O compared to the optical image (d) of particle track C2009,4,59 made by impact of a sample from comet Wild 2 into Stardust aerogel. The same false color bar is used in all three absorbance maps. All four maps show identical area (same distance scale). The original aerogel surface exposed to the comet is on the left. These images show that the impacting comet particle contained aliphatic organic materials that were distributed into the aerogel surrounding the track during the impact event.

Figure 5. Computer-generated image of the complete O/OREOS nanosatellite. Right: photograph of the flight prototype. The wheel near the left end of the satellite is the SEVO sample carousel with 24 cells (that appear as round holes) for thin-film organic samples.

    Louis Allamandola Louis Allamandola
    Murthy Gudipati

    Andrew Mattioda

    Scott Sandford

    Max Bernstein

    Jan Cami

    Jamie Cook

    Jason Dworkin

    Els Peeters

    Nathan Bramall

    Stefanie Milam

    Michel Nuevo

    Joseph Roser

    Objective 1.1
    Formation and evolution of habitable planets.

    Objective 2.1
    Mars exploration.

    Objective 2.2
    Outer Solar System exploration

    Objective 3.1
    Sources of prebiotic materials and catalysts

    Objective 3.2
    Origins and evolution of functional biomolecules

    Objective 3.4
    Origins of cellularity and protobiological systems

    Objective 4.3
    Effects of extraterrestrial events upon the biosphere

    Objective 7.1
    Biosignatures to be sought in Solar System materials

    Objective 7.2
    Biosignatures to be sought in nearby planetary systems