Heating of dust particles enclosed in icy material

“Dirty ice” is known to exist on the surfaces of comet nuclei and on the surfaces of many natural satellites in the outer solar system. In this paper the thermal behaviour of dark dust particles enclosed in icy material is studied under the assumption that a certain fraction of the solar radiation can penetrate the ice and heat the particle directly. It is found that the area contact between the particle and the ice must be quite small in order to heat even a “large” particle significantly above the temperature of the surrounding bulk ice. Under realistic assumptions for the area contact parameter micron-sized particles become hardly hotter than the surrounding bulk ice.