a) Surface-brightness distribution as a function of fractional radius. The solid line is the full set of intensities from a spherical model atmosphere with T_eff = 5000 K, log g = 2.0 and M_⋆ = 5   M_⊙. The dashed line has removed intensity values for r/R_⋆ ≥ 0.995 and then renormalized the fractional radius to the interval 0 − 1. The dotted line has removed intensity values for r/R_⋆ ≥ 0.98 and then renormalized the fractional radius to the interval 0 − 1. b) Surface-brightness distributions from panel a) plotted as a function of μ, with the lines having the same meaning as in the a) panel. c) Fits to the surface-brightness distributions in panel b) using Eq. (2). The lines have the same meaning as the other two panels.