Dynamics of Granular Asteroids 
Ishan Shrma, James T. Jenkins, Joseph A. Burns 
Department of Theoretical and Applied Mechanics 
Cornell University, Ithaca, NY 14853 
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Recent research has led to the now accepted view that most asteroids are not 
coherent solid objects but are, in fact, loose conglomerates, best described 
as gravel piles. Compared to solid objects, granular ones tend to deform more 
and, possibly, to dissipate more energy. Both these facts might have a significant 
influence on the dynamics and shape of granular asteroids. To study the dynamics 
of a granular asteroid, 
we begin by assuming that the asteroid deformes  homogeneously. We then consider 
different kinds of material behaviours. For example, we model the granular pile 
as a collection of colliding, inelastic, rigid spheres or as a dense packing of 
frictional spheres in contact. The type of dynamical situations we consider include 
pure spin about a principal inertia axis, free Eulerian precession,  and planetary 
fly-by's. In these, we determine the position and velocity of the center 
of mass and/or the homogeneous deformation as functions of time.