Near-infrared NH₃ and HCN absorption cross-sections (smoothed for clarity). Left: NH₃ cross-section (red solid) compared to H₂O (blue dashed), at 1000, 1500 and 2000 K (darker implies higher temperature) and 1 mbar. Right: HCN cross-section (orange solid) compared to H₂O under the same conditions. Shading indicates the WFC3, K-band, and Spitzer IRAC bandpasses. The plotted wavelength range is observable by JWST NIRISS/NIRSpec. Diagnostic strong NH₃ and HCN absorption features are annotated.