Stokes Number of pebbles (solid lines), the drift limit (dotted lines) and fragmentation limit (grey dashed line) at different times (colours) for the unperturbed disc. The different viscosities are shown from left to right (setups: V1noP, V5noP & V10noP). Vertical lines show the position of various ice lines. The fragmentation limit is only shown for t = 0.5 Myr because it is almost constant over time.