H₂O line ratios with respect to the o-H₂O (3₁₂ − 3₀₃) line at 1097 GHz measured at the R2 shock position, corresponding to the compact component, and at the offset position (10′′, −10′′) with respect to R2, corresponding to the extended component. The HIFI water line intensities are integrated in the line wings (see Fig. 10) at the original angular resolution of the spectra (see Table 2), while the intensity of the H₂O line at 1670 GHz in the two gas components is measured from the PACS map by averaging over 19′′. The intensity of the H₂O (2₁₁ − 2₀₂) line at 752 GHz associated with the compact component is corrected for the beam size ratio with respect to the 1097 GHz line (28′′/19′′), assuming the source to be point-like.