Simulation and Analysis of a Comet's Atmospheric Entry, Impact, and Consequences

Simulations of a 2.0-km comet striking Earth on solid ground and on ocean waters have been conducted. Models include hydrostatic equilibrium profiles of temperature, pressure, and densities for atmosphere, ocean, and silicates, in order to accurately predict impact consequences. Phase changes, such as melting and vaporization, combined with the material's tensile, shear, and compressive strength responses, under high temperature and high strain conditions, along with anisotropic responses, are considered in greater detail than previous work. Our simulations illustrate the erosion of the comet and the creation of a dusty tail, the breakup of the comet into fragments, the erosion of some of the fragments, and the survival of others. The entry of fragments into the stratosphere and their flattening is also demonstrated. For the first time, we also present results of the impact at a ground/ocean interface, where saturation is a driving factor in the resulting shape of the impact crater.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.