Continuum-normalised spectrum between 7.2 μm and 8.1 μm versus the best-fit LTE model for f_bg(C₂H₂) = 0.2. The model includes the C₂H₂ ν₄+ν₅ combination band, CH₄ gas, and CH₄ ice. Only the spectral region indicated in by the pink shaded area was included in the fit in order to avoid the effects of Pf α contamination, CS absorption, and further systematic uncertainties in the continuum estimation. The grey shaded area in the bottom panel indicates the 68% interval of the residuals.