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M. Küppers (Physikalisches Institut, Universität Bern, Switzerland)
We have developed a Monte-Carlo model of the evolution of the regolith on atmosphereless solar system bodies. The main model input parameters are the mass and velocity distribution of impacting meteorites and shape, gravity, and strength of the surface material of the target. The model then uses scaling laws for crater size and crater ejecta velocity and size (e.g. Housen et al. 1983, J. Geophys. Res. 88, 2485) to derive regolith properties like depth of the regolith layer, particle size, and residence time in a surface layer.
The well-studied regolith of the Earth's moon was used as a test case for the model. The depth of the regolith layer, particle size distribution and horizontal transport of regolith agree well with observations.
We will show the application of the model to Asteroid 433 Eros. Images from the NEAR mission somewhat constrain the strength of the material on Eros, a parameter which is completely unknown for most Asteroids. The variation of impact rates and gravity over the surface of the object is taken into account. Trajectories of ejecta from large craters are calculated numerically. Results will be presented as maps of the regolith depth on the surface and predictions of the size distribution of regolith particles.
The author(s) of this abstract have provided an email address for comments about the abstract: kueppers@phim.unibe.ch