Upper left: normalised flux for the RSG HD 95687 (grey), as observed with VLT/AMBER for the K − 2.1 µm bands. Our initial best-fit model with β = −1.10 and γ = 0.45 is shown in red, corresponding to the parameters of the density profile by Harper et al. (2001). The pure MARCS model fit is shown in orange. As expected, the fluxes are well represented by both our fit and MARCS. Upper right: same as the upper left panel, but for the K − 2.3 µm band. Lower left: same as the upper left panel, but for the |V|² and a baseline of B = 60.8 m. Lower right: same as the lower right panel, but for the K − 2.3 µm band and a baseline of B = 63.2 m. Our model can represent the data better than simple MARCS.