Contour plots of the radial emissivity parameter q and the break radius r_b (left) and the spin a (right), respectively. Data were created by a “complex” model with radially stratified ionisation, isotropic irradiation, and angular emissivity. A single-ionisation model with power-law radial emissivity was used to fit the data. The individual contours correspond to 1σ, 2σ, and 3σ level, respectively.