Formation of a permanent dust mantle and its effect on cometary activity

Numerical simulations have been conducted for the evolution of one-dimensional comet nucleus models within the Comet Halley orbit, allowing for amorphous ice crystallization, in order to investigate the growth of a dust mantle on the surface of a comet nucleus initially composed of dusty, amorphous water ice. The results obtained indicate that the activity of a dust-covered nucleus may largely be due to exposed patches of ice, as well as from such craters as those found by Giotto in Comet Halley. The insulation afforded by the dust mantle leads to a slower crystallization of the amorphous ice than that which would hold in the case of a bare icy nucleus. 31 references