Description of the dust surface density used in the nine different models, based on the surface density derived by Augereau et al. (2001) for the parent bodies (PB, black line). Each of the nine models is made of three parts delimited by the two vertical dotted lines at 50 AU and 115 AU: an inner region (purple curves) following either a power law or the PB distribution, a common intermediate region following the PB distribution, and an outer region following a power law (green curves).