Examples of the spiral shape for the CIRs as a function of the winding radius, r₀. The figure displays the centroid of four different CIRs with distance from the star. The star is the shaded magenta circle. The CIRs are in the equatorial plane, shown here as seen from above. The two larger dotted circles are reference circles at 2R_∗ and 4R_∗. The different spirals are distinguished by different winding radii as labeled. Lower values of r₀ place the transition from a cone-shaped CIR to a spiral one closer to the star; higher values of r₀ indicate that the CIR has small curvature until achieving large distances from the star.