Left panel: random lognormal distribution of the rate coefficient of the reaction H + H + M → H₂ + M, evaluated at 1 mbar and 1000 K, for the models where (photo)chemical kinetics is perturbed. Right panel: random lognormal distribution of K_zz around the nominal value for the HD 189733b models where vertical mixing is perturbed, where the black histogram refers to the whole set of 3000 runs, the blue one to the set of converged runs, and the red one excludes those runs with a relaxed convergence (see text). The runs actually considered for the sensitivity analysis are those converged but excluding the right wing to have a symmetric distribution (blue area). In both panels, the vertical dotted line indicates the nominal value and the shaded gray area the range ±1 σ around it.