ENERGY DISTRIBUTION BETWEEN THE ATMOSPHERE AND THE EARTH›S SURFACE FOR TRANSIENT IMPACT VARIANTS OF LARGE COSMIC BODIES

Abstract

There are two ultimate impact scenarios for large space bodies: a crater-forming impact, when almost all of the initial kinetic energy of the body goes to the formation of a crater, and the “meteor explosion”, in which the energy is released in the atmosphere. In transient scenarios, the loss of energy in the atmosphere is significant, but the body reaches the Earth›s surface with enough energy to form a crater. The hazardous consequences of such impacts must be assessed with this energy separation in mind. On the basis of the performed calculations and a simple quasi-empirical model of the interaction of space bodies with the atmosphere, scaling relations for determining the fraction of energy lost by a space body during a passage in the atmosphere in transient modes are proposed. The results provide an opportunity to properly describe the appearance and growth of a crater as the impactor size increases, which is currently described incorrectly in online calculators of asteroid-comet hazard, and to adjust the estimates of other dangerous consequences for transient variants.