Flux measurements, spectral energy distribution and relative emissivity spectra (in inset) of the Pluto/Charon system, for the one- and two-component NEATM fits. Left: one-component fit, with following parameters: D = 2294 km, p_v = 0.64, η = 1.38. Right: two-component fit, with fixed diameter/albedo for Charon. Model parameters are: Charon, D = 1207 km, p_v = 0.362, η = 1.20; Pluto, D = 2225 km, p_v = 0.61, η = 2.56. In the left panel, different colors show NEATM fits applied to the conditions of the different observations (Spitzer, Herschel, and ALMA). In the ring panel, the individual model Pluto (red) and Charon (green) components are shown for the Herschel conditions, and the total model flux (black) is shown both for Herschel (solid line) and Spitzer (dashed line).