Academia Sinica Logo

Interstellar dust has long been modeled with separate silicate and graphite/amorphous carbon components. In this talk, I will argue that initially distinct populations of stardust get rapidly homogenized in the ISM into a composite material ("astrodust"). I will show that the astrodust+PAH model is compatible with current observational constraints on dust extinction and emission in the diffuse ISM and that it provides a more natural explanation for the observed polarized emission than do two-component models. I will discuss implications for the lifecycle of dust in galaxies.