Evolution of circumstellar discs in young star-forming regions
  The evolution of circumstellar discs is influenced by their surroundings. The
relevant processes include external photoevaporation due to nearby stars, and
dynamical truncations. The impact of these processes on disc populations
depends on the star-formation history and on the dynamical evolution of the
region. Since star-formation history and the phase-space characteristics of the
stars are important for the evolution of the discs, we start simulating the
evolution of the star cluster with the results of molecular cloud collapse
simulations. In the simulation we form stars with circumstellar discs, which
can be affected by different processes. Our models account for the viscous
evolution of the discs, internal and external photoevaporation of gas, external
photoevaporation of dust, and dynamical truncations. All these processes are
resolved together with the dynamical evolution of the cluster, and the
evolution of the stars. An extended period of star formation, lasting for at
least 2 Myr, results in some discs being formed late. These late formed discs
have a better chance of survival because the cluster gradually expands with
time, and a lower local stellar density reduces the effects of photoevaporation
and dynamical truncation. Late formed discs can then be present in regions of
high UV radiation, solving the proplyd lifetime problem. We also find a
considerable fraction of discs that lose their gas content, but remain
sufficiently rich in solids to be able to form a rocky planetary system.
