Histograms of fit parameters ((a) porosity factor K; (b) single-scattering albedo ϖ₀; (c) and (d) are b and c in Eq. (5); (e) slope angle ; (f) and (g) are B_S0 and h_S in Eq. (8); and (h) and (i) are B_C0 and h_C in Eq. (9)) of the nine-parameter Hapke model over the full phas- angle range (1°–144°) with K constrained to be larger than or equal to 1. The peak values of (a)–(i) were then used as the initial guess values, and the fitting results are shown in (j).