DPS 35th Meeting, 1-6 September 2003
Session 31. Asteroid Dynamics I
Oral, Chairs: W. F. Bottke, Jr. and J. S. Stuart, Friday, September 5, 2003, 10:30am-12:00noon, DeAnza I-II

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[31.02] Numerical Modeling of Asteroid Collisional Evolution: Recent Results

D. P. O'Brien, R. Greenberg (University of Arizona)

We have developed an advanced numerical collisional evolution simulation based on the algorithm of Petit and Farinella (1993), which includes a more detailed treatment of collisional outcomes (i.e. cratering debris and hyper-catastrophic collisions) than our previous modeling (O'Brien and Greenberg, ACM 2002, DPS 2002). Our model also includes the non-collisional removal of bodies by size-dependent radiation forces such as the Yarkovsky effect. Such a model must be able to fit a variety of constraints, including the observed main-belt size distribution, the observed NEA population (which consists of bodies removed from the main belt), the lifetimes of meter-scale bodies (as inferred from the cosmic ray exposure ages of meteorites), estimates of the strength of asteroids from analytical and numerical models and laboratory experiments, and current estimates of the non-collisional removal rate of bodies from the main belt. In addition, the resulting main belt population must be consistent with the size distribution of craters on observed asteroids. We are now able to achieve a good fit to all of these constraints with our model. Cratering debris have a significant effect on the final evolved population and cannot be ignored. Furthermore, we find that Q*D by itself is not an adequate parameterization of asteroid strength: Different combinations of the parameters Q*S and fKE which give the same effective Q*D can give significantly different collisional outcomes. We will present our most recent results, and discuss their implications for the collisional and dynamical evolution of the main belt and for the relation between the NEA and main-belt populations.

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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.