Top: gas and pebble surface densities as a function of orbital distance at different disk ages. Bottom: pebble sizes and Stokes number as a function of orbital distance at different disk ages. In both panels, Rocky_peb = 1 mm and S_peb = 1, which correspond to our nominal values. The sharp drop in the Stokes number in the inner regions of the disk is due to the snow line transition where we set the size of silicate pebbles to 1 mm.