1D disc evolution models

Performing population synthesis, we find that under the combined losses of internal and external photoevaporation, discs are too short lived. To match observational constraints, future models of disc evolution need to include either or all of the following processes: infall of material to replenish the discs, shielding of the disc from internal photoevaporation due to magnetically-driven disc winds, and extinction of external high-energy radiation.

Nevertheless, disc properties in low-external photoevaporation regions can be reproduced by having more massive and compact discs. Here, the optimum values of the alpha viscosity parameter lie between 3*10^-4^ and 10^-3^ and with internal photoevaporation being the main mode of disc dispersal.