The destruction of dust grains in collisions of a supernova with a circumstellar medium

Dust grains exist, if not abundantly, in systems composed of a Type II supernova and a circumstellar medium (CSM). The grains, however, may subsequently suffer intense sputtering by X-ray emitting plasmas during the collision of the supernova ejecta with the CSM. An approximate expression is obtained for the amount of grain erosion in both the blast-shocked CSM and the reverse-shocked ejecta, assuming their self-similar interaction. The distortion of the grain size distribution is also calculated. The infrared fluxes expected from the blast-shocked CSM are roughly estimated. (author)