Dust destruction in the transition region between stellar wind and interstellar medium

Simple theoretical considerations about three dust destruction mechanisms in shock fronts (thermal evaporation, destruction by sputtering due to gas-grain collisions and destruction by grain-grain collisions) are applied to the terminal shock between the wind of a red giant and the interstellar medium. A realistic size distribution of the dust grains is taken into account and the effects for charged grains caused by the presence of magnetic fields are studied, including a discussion of the acceleration of charged dust grains (betatron acceleration in the downstream region and acceleration by "magnetic reflection" across the shock). All dust destruction mechanisms are found to be unimportant in the considered situation. Thus, the dust formed in the massive winds of red giants is injected into the ISM without substantial losses.