Top panel: HD abundance structure for a disk model, with M_disk = 2.3×10^-2M_⊙, ψ = 0.3 and h_c = 0.1, which is identical to Fig. 3. Colour indicates the number density of HD with respect to the total gas density. The coloured lines correspond the HD 1–0 (blue) and HD 2–1 (light blue), respectively. Solid contours indicate where 25% and 75% of the emission originates from. The dashed (dash-dotted) lines show the τ = 1 surface for the line and continuum opacity, respectively. Bottom panel: HD abundance structure of the same initial model, where the vertical structure is now determined by eight iterations of the hydrostatic solver of DALI.