Example of a model fit. The spectrum in black is a VIRTIS-H spectrum of comet 67P obtained on 22 July 2015 (T1_ 00396220410), without the regions excluded from fitting or presenting water and CO₂ emission lines (the full spectrum is given in Fig. 2). The model fit to the continuum, which corresponds to the sum of scattered light (plain orange line) and thermal radiation (dashed green line) is shown in red. Retrieved parameters are T_col = 295 ± 1 K (corresponding to S_heat = 1.194 ± 0.003), A = 0.068 ± 0.001, and = 2.3 ± 0.1% per 100 nm.