This program of research will lead to a clear understanding of the evolution of organic matter in dust in the environments of objects which are realistic analogs of the early Solar System. This research is being carried out in collaboration with groups at NASA Ames Laboratory, the Laboratory for Space Research, Groningen, and Leiden University. This shock heated the accreting material to temperatures which ranged from about 5000K in the outer solar system to above 10,000K in the inner solar system. These reactions are important sources of species that are not synthesized efficiently by ion-molecule reactions, including the simplest hydrocarbons. Thus methane and acetylene, which account for a negligible fraction of the gas-phase carbon in cold regions, may be quite abundant behind a shock.
Shocks also transform virtually all of the gas-phase oxygen into water.
UV photons ionize most of the heavy elements, and this presumably has a significant affect on the gas-phase chemistry. The absorption of UV radiation by icy mantles on dust grains drives photolytic reactions which lead to the formation of organic material on the grain surfaces. Shocks can vaporize dust grains. Faster shocks can vaporize volatile organics, refractory organics, and even the refractory mineral cores of the grains. The goal of our research is to model the gas and grain surface chemistry of shock-heated material in the primitive solar nebula.