Spectral line energy distribution of the H₂O lines detected with SPIRE, the black curve represents the data. For the 1₁₁ → 0₀₀ line, only the absorption part is included. The line with upper energy level 249 K is 3₁₂ → 3₀₃. Model predictions are included, the blue and light-blue curves show the contribution from C_core and C_outer, respectively. The red curve indicates the sum of the fluxes predicted by the two models.