Observed and synthetic Uranus spectra. Black: continuum-divided spectra (solid: range scan; dashed: HssO line scan; dotted: OT line scans) and best-fit model (red) with D/H = 4.41 × 10^-5. Synthetic spectra for different D/H ratios but for the same thermal profile to illustrate the sensitivity to this model parameter are shown as green solid lines for D/H = 3.4 × 10^-5 and D/H = 5.4 × 10^-5 (3σ) and blue solid lines for D/H = 4.07 × 10^-5 and D/H = 4.75 × 10^-5 (1σ). The spectral line around 56.33 μm is caused by stratospheric H₂O emission and is not included in the model. The R(2) line has been measured by ISO-SWS.