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F. J. Ciesla, L. L. Hood (Lunar and Planetary Laboratory, University of Arizona)
Chondrules are small (~ 1mm), spherical, silicate particles that are significant components (up to 80% by volume) of ordinary chondrites. They are among the first solids to have formed in the solar nebula; therefore understanding their histories will provide insight into the processes that took place during the first few million years of our solar system. Experimental studies and laboratory analyses have demonstrated that chondrules were brought from relatively low temperatures to their melting points on timescales of seconds or minutes and cooled at rates between 100 and 1000 K/hr. The time scales for processing particles in this manner can not be explained by nebula wide events, and therefore must be due to local, transient events in the nebula. The leading mechanism to explain the formation of chondrules is nebular shocks, though the source of the shocks is still debated. We present numerical simulations showing that shocks can produce the heating and cooling histories of chondrules. The scale size of the shock is dependent on the pre-shock environment that chondrules formed in. These imposed scales allow us to evaluate what processes may have been responsible for the shocks.
This work is supported by a grant from NASA's Origins program.
The author(s) of this abstract have provided an email address for comments about the abstract: fciesla@lpl.ariozna.edu