Scattering diagram of light with λ = 580 nm impinging on the dust particle with R = 0.168 μm. This particle gives the maximal dimensionless efficiency factor for the radiation pressure averaged over the stellar spectrum. For x_M = 2πR/λ< 1.38 scattering is predominantly back to the source. Considered situation corresponds to x_M ≈ 1.820 and the scattering diagram has the usual preponderance of forward radiation over back radiation (van de Hulst 1981).