Exobiology and Evolutionary Biology

PI: Flynn, George

Some interplanetary dust particles (IDPs) are the most primitive (i.e., least altered by thermal or aqueous processing) samples of the dust that condensed as our Solar System formed that are currently available for laboratory analyses. Many primitive IDPs even preserve interstellar material, as demonstrated by non-Solar D, ¹⁵ N, and 16O contents (detected by Dr. S. Messenger, NASA Johnson Space Center and others). This project has three major objectives:
1) determine the types and abundances of organic matter delivered to the Earth, Mars, and other planets and moons by the IDPs and assess its importance as a source of pre-biotic organic matter for the origin of life (a possibility suggested by Anders, Nature, 1989),
2) compare the organic matter in the most primitive anhydrous IDPs with that in hydrated IDPs and hydrated meteorites to determine the changes in this pre-biotic organic matter brought about by aqueous alteration, and,
3) characterize the organic matter in the most primitive IDPs to understand and constrain the conditions and infer the mechanisms for the production of organic matter in the early Solar System, and, in the case of organic matter exhibiting non-Solar D/H or δ ¹⁵ N, the production of organic matter in the interstellar medium or around other stars.

The IDPs are small, typically ~10 microns in size, and are dominated by silicate minerals. Thus we require instruments of high-sensitivity to detect and characterize their organic matter. We determine the amount and types of organic matter in these particles using two high-sensitivity, synchrotron-based instruments:
1) a Scanning Transmission X-ray Microscope with a resolution ~35 nanometers to determine the C , N and O abundances and to characterize the organic functional groups by X-ray Absorption Near-Edge Structure spectroscopy, and,
2) a microscope-based Fourier Transform InfraRed spectrometer with a spatial resolution of ~3 to 5 micrometers to determine the organic functional groups.