Figure 2
From: Effect of lift force on the aerodynamics of dust grains in the protoplanetary disk
Parameter space where the dust grains can keep spinning in the R 1 – r d plane. The Stokes regime is between the two dashed green lines. The condition tcol <tspin-down is satisfied above the solid red line. The grains may keep spinning in the blue region. The dotted magenta line represents the line where the condition St = 1 is satisfied.