Debris disks in the Herschel era

Debris disks are dusty disks orbiting mature stars.  They owe their
origin to collisional replenishment by small bodies and as such
represent a major piece in the unfolding story of the nature of
planetary systems.  After their discovery by IRAS in 1982, their rich
and diverse diagnostics have been studied by major ground-based
facilities (VLT, VLTI, and, recently, ALMA) and space missions (HST,
ISO, Spitzer).  The role of Herschel is to offer for the first time
the possibility to study their properties in the main domain in which
they radiate their thermal energy, at an appreciable spatial
resolution.  Building on the important censuses Spitzer has achieved,
Herschel has uncovered the anticipated existence of cold debris disks.
We will discuss in detail the major results Herschel has achieved on
nearby debris disks that can be well resolved spatially, in particular
those of Vega, Beta Pictoris and Fomalhaut.