Maximum Stokes number (top plot) and planetary growth timescale until the pebble isolation mass is reached (bottom plot) as a function of orbital distance, for the disks with the four different initial gas surface densities: α = 10⁻³ (left plot), α = 5 × 10⁻⁴ (middle plot), α = 10⁻⁴ (right plot), and u_f = 1 m s⁻¹. The gray lines show the typical lifetime range of a protoplanetary disk of 3–10 Myr.