Experimental study on the collisional disruption of porous gypsum spheres

Abstract

In order to study the catastrophic disruption of porous bodies such as asteroids and planetesimals, we conducted several impact experiments using porous gypsum spheres (porosity: 50%). We investigated the fragment mass and velocity of disrupted gypsum spheres over a wide range of specific energies from 3 x 10^3 J/kg to 5 x 10^4 J/kg. We compared the largest fragment mass (ml/Mt) and the antipodal velocity (Va) of gypsum with those of non-porous materials such as basalt and ice. The results showed that the impact strength of gypsum was notably higher than that of the non-porous bodies; however, the fragment velocity of gypsum was slower than that of the non-porous bodies. This was because the micro-pores dispersed in the gypsum spheres caused a rapid attenuation of shock pressure in them. From these results, we expect that the collisional disruption of porous bodies could be significantly different from that of non-porous bodies.