Complex refractive indices as a function of wavelength for the dust species considered in this study. Top: the real part of the complex refractive index n(λ). The grey area indicates the range in wavelength used to determine the values of n listed in Table 5. Middle right: the imaginary part of the complex refractive index k(λ). The vertical dashed line at 8μm marks λ_split, which is the boundary between k₁ and k₂, the two constant values of the imaginary part of the complex refractive index used in our recipe. The horizontal black line at unity marks the value we use for k₂. Middle left: the values of k₁ (listed in Table 5) that best reproduce the T_d(s) profiles of the various materials. The symbols are offset horizontally for visibility only. No symbol is shown for SiO, since its temperatures cannot be reproduced by our complex-refractive-index recipe. Bottom: the spectrum of the Kurucz model atmosphere that we use for the host star KIC 12557548, together with thermal emission spectra of dust at different temperatures, all normalised to unity. Also shown is the Kepler response function (not normalised), for which the vertical axis should read “response”.