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C. S. Plesko (UCSC, LANL), E. Asphaug (UCSC), G. R. Gisler, M. L. Gittings (LANL)
We present initial results of simulations of asteroid impacts into a volatile-rich Martian surface, and test the RAGE hydrocode (Gittings et al., 2005) in benchmark scenarios relevant to such models.
RAGE is an Eulerian radiation-hydrodynamics code that runs in up to three dimensions, using a Godunov method to solve the hydrodynamics equations, and adaptive mesh refinement to increase computational efficiency near shocks and boundaries. It incorporates a large variety of detailed equations of state including the temperature-based SESAME tables maintained by LANL.
Our Mars impact modeling effort involves two components: (1) characterizing and validating RAGE models of the propagation of impact shocks in well-characterized laboratory experiments, and (2) building up realistic RAGE models of the Martian surface involving inhomogeneous layers, volatile layers, and atmosphere.
The Mars science goals of these efforts are twofold. The first is to arrive at a robust quantitative examination of impact devolatilization, which has been proposed (Segura et al., Science 2002) as a mechanism for triggering sporadic but intense Martian hydrologic cycles. The second goal is to attempt to relate the geological expression of Martian craters to the nature of sub-surface layering.
Comparison of hydrocode results against analytical and laboratory results are imperative for correct forward modeling, so we have begun by putting RAGE through a series of validation tests. We present model results that show good agreement with laboratory experiments and analytical models, and initial results for Mars crater formation.
This effort is supported by LANL/IGPP (CSP, GRG, MLG) and by NASA PG&G "Small Bodies and Planetary Collisions" (EA).
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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.