Reduced χ² maps from VLTI/MIDI observations of CPD-57° 2874 for all 45 combinations of free parameters of our model (FRACS). The maps are centered on the (=0.54) position and correspond to the distance of 1.7 kpc. Contours are drawn for , with Δχ² = 0.3,1,3. The parameters are ordered as in Table 4. The map scale is given in logarithmic units. Details on the model-fitting procedure are given in Sect. 5.