Reflectance spectrum of Cybele and Themis in albedo units. Within the noise, both spectra looks very similar. Overplotted on the spectrum of Themis is the spectral model included in Fig. 1 of Rivkin & Emery (2010). A similar model is overplotted on Cybele’s spectrum. These models include a thin coating of H₂O ice on surface grains. Notice that models fit very well the left part of the band while at longer wavelengths there are additional absorptions.