Dust temperature, excitation temperature and radiation field for a model with g/d_gas = 1000, and a constant abundance of 10^-7. The red line in panels b), c), e) and f) shows the CO₂ line τ = 1 surface, the blue line shows the τ = 1 line for the dust. Panel d) shows the dust temperature at the height from which most of the emission of the 15 μm Q(6) line originates as function of radius. The vertical blue lines enclose the radii that account for 50% of the emission.