Top left plot, Spitzer 1RS regime for the 14 µm HCN blend. Top right, same plot for H₂O in the 17.12 µm regime. Bottom left, same plot for H₂O in the 17.22 µm regime. Bottom right, H₂O in the 17.36 µm regime. Each transition in the regime is plotted as a dark blue or green line (ortho and para H₂O), red blend for HCN ro-vibrational (LTE treatment, HITRAN database ^(★), dotted magenta line for NH₃ rovibrational (LTE treatment, HITRAN database^(★), dotted khaki for OH (LTE treatment, HITRAN database^(★). The blue solid curve represents the final blended 1RS spectrum (R = 600). Vertical dot-dashed lines delimit the range over which the blend flux is taken in Najita et al. (2013).