Are some meteoroids rubble piles?

TL;DR

This paper investigates whether small meteoroids are rubble piles held together by weak forces, analyzing observational data to determine their structural integrity during atmospheric entry.

Contribution

It provides evidence that meteoroids in the 1-20 meter range are unlikely to be rubble piles, based on disruption behavior during atmospheric entry.

Findings

Meteoroid disruption occurs at higher pressures than expected for rubble piles.

No early fragmentation evidence was found for the Chelyabinsk event.

Benesov meteoroid started disrupting at 50 kPa, not 25 Pa as expected for rubble piles.

Abstract

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.