Extended (left panel) and zoomed-in (right panel) spectra around the 1-propanol transition. Observed spectrum (black) around the targeted 1-propanol transition at 236.138 GHz (purple dotted-line and black dashed-line box) towards the “full-beam” offset position located 0.5′′ away from the continuum peak of IRAS 16293-2422B. Synthetic spectrum of the LTE model is shown in red. The predicted 1-propanol transition shown here is for N(1-propanol) = 1.2 × 10¹⁵ cm⁻² and T_ex = 300 K (see text for more details). Red dotted-lines refer to the position of transitions of identified species detected above 5σ, with the associated species labelled below the spectrum.