Spatial emission profile of HD 169142 in the 11.3 μm PAH band. The red curve shows the observed PSF profile (see Appendix F), and the black curve shows the employed approximation thereof used in the 2D convolution of the model (see Sect. 5.2.5). The solid gray curve shows the ring model that best fits the observed central peak (ring radius 0."14). The dashed gray curve shows the best-fit model with the ring radius fixed to the value observed in the SPHERE data (0."17).