Are some meteoroids rubble piles?
Jiří Borovička
Paper presented at the IAU Symposium 318 Asteroids: New Observations, New Models (Honolulu, USA, August 3-7, 2015). Accepted for publication in the Proceedings of the International Astronomical Union arXiv:1510.07869
“The possibility that some meteoroids in the size range 1 – 20 meters are rubble piles i.e. assembles of boulders of various sizes held together only by small van der Waals forces, is investigated. Such meteoroids are expected to start disrupting into individual pieces during the atmospheric entry at very low dynamic pressures of ~ 25 Pa, even before the onset of ablation. The heterogeneous bodies as Almahata Sitta (asteroid 2008 TC3) and Benesov are primary candidates for rubble piles. Nevertheless, by analyzing the deceleration, wake, and light curve of the Benesov bolide, we found that the meteoroid disruption started only at a height of 70 km under dynamic pressure of 50 kPa. No evidence for a very early fragmentation was found also for the Chelyabinsk event. “
