In section 6. Interstellar and circumstellar matter
Bow shocks and detached shells in the far-infrared
The mass loss from evolved AGB and supergiant stars is known to be rapidly variable and to cause bow shocks whose shape depends on the stars' peculiar motions relative to the surrounding interstellar medium. This can be observed in far infrared dust emission as shown by Cox et al. in this highlighted article. The authors study the emission from 78 evolved stars using the PACS instrument on Herschel and find stand-off distances for the bow shocks that are consistent with hydrodynamical simulations. These results are used to infer the interstellar density in the vicinity of the stars.