Properties of model and observed spectra. The circle, triangle and square markers indicate models with superwind radii of 200, 500 and 2500 AU respectively. The blue, red, teal and green curves are for models with mass loss rates of 1 × 10^-5 M_⊙/yr, 5 × 10^-5 M_⊙/yr, 10 × 10^-5 M_⊙/yr or 15 × 10^-5 M_⊙/yr respectively. All other model parameters are listed in Table 3. The observations are shown as in Fig. 8.