What is the source of the large dust shells seen around some red giants and red supergiants?

Question

Quizplus · Accepted Answer

The large dust shells seen around some red giants and red supergiants are caused by material from winds from these same stars. As these stars expand and evolve, they eject material into space through powerful winds. This material can then form dust shells around the stars. The large dust shells seen around some red giants and red supergiants are usually the result of the material ejected from these stars by their strong stellar winds. As these stars undergo nuclear fusion and expand, their outer layers are pushed out into space by the force of their own radiation and stellar winds. These ejected materials can form into large clouds of dust and gas surrounding the star, which can be observed in infrared and other wavelengths as a "dust shell." This process is believed to be the source of most of the dust in the Milky Way galaxy.

What Is the Source of the Large Dust Shells Seen