The cloud structure at the substellar point (θ = 0°, ϕ = 0°) for the two giant gas planets HD 189733b (red) and HD 209458b (blue). In the first three panels, the dashed lines indicate the properties at the right-hand axis, the solid lines to the left-hand axis. First panel: gas temperature T_gas [K] (left), mixing time-scale τ_mix [s⁻¹] (right); second panel: nucleation rate J_* [cm⁻³ s⁻¹] (left), number of dust particles n_d [cm⁻³] (right); third panel: mean grain size 〈a〉 [ μm] (left), drift velocity for mean grain size 〈v_dr〉 [cm s⁻¹] (left); fourth panel: material volume fraction V_S/V_tot for HD 209458b; fifth panel: material volume fraction V_S/V_tot for HD 189733b. The colour coding for the third and fourth panels is TiO₂[s] – solid very dark blue; Al₂O₃[s] – solid blue; CaTiO₂[s] – solid purple; FeS[s] – dotted green; FeO[s] – dashed green; Fe[s] – solid green; SiO[s] – dashed brown; SiO₂[s] – solid brown; MgO[s] – dashed dirty orange; MgSiO₃ – dashed orange; Mg₂SiO₄ – solid orange.