Ratio between Ceres’ phase curve at α = 20° and α = 80° (Phase Curve Ratio) against wavelength (VIS: black, IR: red). Gaps in the spectrum correspond to the order-sorting filter positions and VIS-IR junction of the instrument. We limit our analysis to λ > 0.465 μm because of increasing instrumental noise at the shortest wavelengths and λ < 4.065 μm because of the contribution of the thermal emission longward of this value.