  Debris discs are commonly detected orbiting main-sequence stars, yet little
is known regarding their fate as the star evolves to become a giant. Recent
observations of radial velocity detected planets orbiting giant stars highlight
this population and its importance for probing, for example, the population of
planetary systems orbiting intermediate mass stars. Our Herschel survey
observed a subset of the Johnson et al program subgiants, finding that 4/36
exhibit excess emission thought to indicate debris, of which 3/19 are
planet-hosting stars and 1/17 are stars with no current planet detections.
Given the small numbers involved, there is no evidence that the disc detection
rate around stars with planets is different to that around stars without
planets. Our detections provide a clear indication that large quantities of
dusty material can survive the stars' main-sequence lifetime and be detected on
the subgiant branch, with important implications for the evolution of planetary
systems and observations of polluted or dusty white dwarfs. Our detection rates
also provide an important constraint that can be included in models of debris
disc evolution.
