Mass of the size distribution per logarithmic interval as a function of the grain mass in units of number of initial grains. The curves are at 10⁴, 3×10⁴, 10⁵, 3×10⁵, 10⁶, 3×10⁶, 10⁷ yr continuously increasing their mass center. The gas density is n = 1.3 × 10¹¹ m^-3, the turbulent speed v_L = 90 m/s, and the core radius is R_c = 22.7 kau. The gray shading denotes the spread in 10 runs. The initial monomers have a size of 0.05 μm. Only data up to 1 Myr are used in this paper.