SED of AC Her. The gray dot-dashed line shows the input Kurucz model, reddened with an interstellar contribution of E(B − V) = 0.135 (see Sect. 3). The dotted blue line is the best single-power-law model (see Sect. 6.2). The dashed red line corresponds to our base model (i.e., the best double-power-law model obtained in Sect. 6.3). The full green line is the best-fit model with the alternative dust composition (Sect. 6.3.2). The inset shows a zoom-in of the near- to mid-IR wavelength range. We note that the ISO spectrum is included in our fit through the indicated anchor points (see the legend).