Simulated moats and wind tails around a boulder on the surface of comet 67P, for various sets of model parameters. Each panel shows the situation after the insertion of a particle wind with an integrated areal flux density of 100kgm⁻². (a) Reference case: rotated cuboid boulder, particles with radii R = 3 … 6 cm, Young’s modulus Y = 10⁵ Pa, restitution coefficient e_r = 0.2, triplet of friction coefficients μ/μ_r/η_r of 1.0/1.0/1.0, cohesive energy density ω = 0.028 J m⁻², insertion speed of particle wind i_ins = 0.5 ms⁻¹. (b–h) Cases, where one of the model parameters (given in the label of the subfigure) has been changed with respect to the reference case. Graphical representation as in Fig. 6. Orange arrows indicate additional local depressions in the low friction case.