Combined best-fit LTE model for ¹²CO₂, ¹³CO₂, C₂H₂, ¹³CCH₂, HCN, and OH emission in source A+B (red shaded region) overlaid on the continuum subtracted data with an arbitrary flux offset (black). Prominent emission lines are labelled. Best-fit results for individual molecules are shown as the coloured lines below, with the horizontal bars indicating the regions of spectrum used for fitting. Extinction by CO₂ ice has been included in the models, which suppresses the flux from the CO₂ gas P-branch (see Sect. 2.4).