Thermal emission of the amorphous carbon nano-grains population (aC1, aC2, VSG) of the THEMIS model (blue), and of the entire THEMIS grain population including larger 100 nm-sized carbon (aCH/aC) and silicates (aSil/aC) grains (pink), for different distances to the central star. The SED units are erg/s/H which is the emission per proton for each grain population. See papers Habart et al. (2021) and Jones et al. (2017) for more detail on the different grain species considered in THEMIS.