Variation of the dust layer thickness as a function of the heliocentric distance for the sphere is estimated in Model B. The aggregate size is 10⁻³ m and the initial dust layer thickness is 2 × 10⁻³ m. The left and right panels represent the cumulative thicknesses at pre- and postperihelion branches, respectively. The results shown are for five surface facets at different latitudes on the sphere. See more details in the text.