CO ladder for HH 46. The data points are as in Fig. 17. The dashed black curve is the model flux for the UV component for temperatures from the Kaufman et al. (1999) grid. The dashed coloured curves are the same, but for the temperature approximation from Eqs. (6) and (7), using different heating efficiencies. The solid red curve combines the dashed red curve with the passive and shock curves from Fig. 17.