Disk structure of the fiducial model but with C/O = 1.5. Top panels: Gas density, gas-to-dust ratio, and gas temperature. Bottom panels: Normalized UV field G₀ (Habing units) and the abundance of H₂O and C₂H₂. The white lines indicate the 300 K and 700 K gas temperature contours. The bottom solid red line shows the dust optically thick surface (τ_dust = 1 at 14 μm), while the dashed red line represents the surface where τ_line = 1. The red contours correspond to 80% of the total emitting flux. The dashed orange line in the bottom panels indicates the H/H₂ transition, sometimes difficult to distinguish from the dashed black line G₀ = 10⁵.