Experiments in the distribution of launch sites for dust particles, for the case ﹩{e}_{{\rm{planet}}}=0.7﹩. If dust grains are launched strictly from the periastra of parent bodies, then all orbits are apsidally aligned (left column of panels; symbol meanings in the h–k plot are identical to those in Figure 1). If dust grains are launched at parent body mean anomalies ﹩{M}_{{\rm{p}}}﹩ that are uniformly distributed between 0 and 2π, the preference for apsidal alignment is muted (right column of panels). Our standard model assumes that dust grains are launched at parent body true anomalies ﹩{f}_{{\rm{p}}}﹩ that are uniformly distributed between 0 and 2π, and represents an intermediate case (middle column of panels). The top row displays corresponding scattered light images, observed at alt = 10° and az = 0° for our standard vertically thin disk with ﹩\max {i}_{{\rm{p,free}}}=0.02\,{\rm{rad}}﹩. Each nearly edge-on disk, as traced by a white contour of constant surface brightness, resembles a “fan” or “moth”; the wings of the moth are angled more sharply downward as dust particle orbits are more strongly apsidally aligned (reading right to left). Note the “double winged moth” that appears when dust grains are launched exclusively from parent periastra (top left). The middle row features scattered light images observed at alt = 0° and az = 90° for a vertically thicker disk with ﹩\max {i}_{{\rm{p,free}}}=0.15\,{\rm{rad}}﹩. The center panel features an inner “ship” surrounded by its “wake,” as detailed in the main text. Brightness asymmetries and vertical asymmetries across the ship-and-wake are magnified as dust grain launch sites concentrate toward parent body periastra (reading right to left).