Scaling of the wall shear stress exerted on planetesimals with varying sizes as a function of orbital distance, r. Here, we assume an orbital eccentricity of e = 0.1. The black dashed line marks the 25 Pa limit for erosion given by Paraskov et al. (2006). The orange dashed line marks the 0.96 Pa limit of the tensile strength of dust layers on comets given by Skorov & Blum (2012). The solid curves with varying colors correspond to varying planetesimal sizes.