Cometary and meteorite swarm impact on planetary surfaces

The impact-induced deformation from hypothetical cometary objects having initial densities in the 0.01 to 1 g/cu cm range and heats of vaporization in the approximately 2 kJ/g (corresponding to water) to approximately 10 to the 7th J/g range is examined for impacts in the 5 to 45 km/s range. Even though the direct effect of an atmosphere is neglected, the atmosphere may in fact cause a cometary object to break up into a shower or equivalent very porous impactor. Besides examining the partitioning of impact energy into internal energy of the impacted planet and impacting cometary material, calculations are made of the relative efficiency of shock-induced melting and vaporization by comets on planetary surface materials and the mass loss from a given planet for various escape velocities.