Difference in water density (left) between the reference T Tauri model (n_sp,1) and the model with new rate constants with accurate description of atom tunneling (n_sp,2) for the reaction H₂ + OH → H₂O + H according to Table 2. The black dashed line shows a difference of 0.5 dex in water abundance in the T Tauri disk model that uses the new rate constants (right); this is to be compared to Fig. 5 (we note the different scale). The yellow dashed contour outlines the region below which 300 monolayers of ice exist.