Degree of linear polarization p_L(θ) as a function of the scattering angle θ (in degrees). The empirical p_L(θ) function from Sparks et al. (2008) is shown as a solid curve (extrapolated to small scattering angles), together with a classical Rayleigh scattering function with p_max = 0.50 (dashed curve). The photometric Henyey-Greenstein phase function Φ(θ) is represented for g = 0.538 using a dotted curve.