H₂O (solid lines) and CO₂ (dashed lines) profiles in a time-dependent Enceladus source model, as compared to observations, making use of the H08 chemical scheme. Left panel: results aimed at fitting the H₂O observed with Herschel. The profiles are initialized at their steady-state values for a OH flux of 5.1 × 10⁶ cm^-2 s^-1 (black curves). The different curves correspond to evolution with four different combinations of τ and t₀. The red circles show the H₂O profile in the (τ = 30 yr, t₀ = 96 yr) case calculated in presence of an additional loss of H₂O to the haze (see text). Right panel: results aimed at fitting the H₂O observed with Cassini/CIRS. The black curves correspond to the steady state profiles obtained with an OH flux of 5.1 × 10⁶ cm^-2 s^-1. Evolution of these profiles for two different (τ,t₀) combinations are shown, as well as the resulting H₂O profile, when a loss to the haze is taken into account for the (τ = 30 yr, t₀ = 55 yr) case (green dots). Upper limits on H₂O thermospheric abundance by Cui et al. (2009) are also shown as arrows.