Meteorite Strewn Fields from Asteroid Airbursts

Abstract:

The distribution of meteorites ejected from an asteroid during atmospheric entry and airburst was simulated using the ALE3D hydrocode. The results from the simulation of asteroid 2008 TC3 were compared to the observed strewn field of meteorites collected in the Nubian Desert.

Risk and hazard models currently produce damage regions for blast hazards but neglect meteorite debris strike hazard areas. Asteroids smaller than the Chelyabinsk meteor (Ø20m) may burst high enough in the atmosphere that the blast wave is not hazardous by the time it reaches the ground, but there may still be significant hazard from the meteorites. A better understanding of strewn fields could also increase meteorite finds and help provide data on asteroid properties and breakup characteristics.

TC3 in particular showed a somewhat counterintuitive effect where the larger meteorites found near the end of the ground track were spread over a wider cross-range distance than the smaller meteorites found further up-range. The simulation showed that during early break-up relatively small fragments are shed into the wake with low cross-range velocity, but when the back side of the asteroid fails a final burst occurs during which larger fragments are flung out at high cross-range velocity.