Crystallization of Silicate Dust Particles in Comets: Annealing by Shock Waves in Solar Nebula

Abstract

Conditions of shock waves in the solar nebula that heat and crystallize amorphous silicate dust particles have been clarified in detail. Some shock waves are found to be able to crystallize amorphous dust particles. Moreover, in the case of the minimum mass solar nebula model, amorphous dust particles in a closer region whose distance from the sun is less 20 AU may be crystallized, while dust particles in a further region beyond 20 AU cannot be. This result suggests that short period comets formed in a distant region should not contain any crystalline, whereas long-period comets formed in a close region can have; this is consistent with observations.