Photoevaporation of circumstellar discs
          Richard Alexander - IoA, Cambridge, UK
          Cathie Clarke - IoA, Cambridge, UK
          Jim Pringle - IoA, Cambridge, UK

          We investigate the role of photoevaporation in the dispersal of circumstellar discs, in particular looking at models which couple photoevaporation by the central source to viscous evolution.  We consider potential ionizing sources, and find observational evidence that a strong ionizing flux can be produced.  We model the hydrodynamic evolution of the disc and compare our results to observed SED data, as well as observational constraints on dispersal timescales.