The cometary bombardment on the primitive asteroid belt

In this paper, we estimate the number of catastrophic collisions between asteroids and comets scattered from the Uranus–Neptune zone during the process of planetary accretion. nd that the change in slope at ≈75 km in the size distribution for non-family asteroids could be produced by an intense bombardment of scattered comets in a short period of time after the accretion of Uranus and Neptune, provided that any asteroid with radius ≤130–150 km received a catastrophic collision by scattered comets. Larger asteroids have probably not received any catastrophic collision, due to the small number of large comets. o estimate that the total amount of mass in the primitive asteroid belt, before the depletion produced by dynamical and collisional processes, was not less than ≈1800 times the present one.