Vertical opacity in our model in the middle stratosphere (at 200 km altitude) as a function of the wavelength for five gases and for the haze with a constant refractive index (m = 1.6 + 0.01i), The grey horizontal bars show where ethane has weak (thin bar), medium (medium bar), or strong (thick bar) absorption features (Maltagliati et al. 2015). The vertical bars delimit intervals where different components can be studied separately: (1) haze and CH₄ between 0.88 and 2.8 µm; (2) haze and CH₃D between 2.8 and 2.95 µm; (3) haze, CH₄, C₂H₂, and HCN between 3.10 and 4.20 µm; (4) haze, CH₃D, and CO beyond 4.2 µm. In the absence of any reliable line list for C₂H₆ in the spectral range of VIMS-IR, the spectral ranges where ethane has strong features cannot be studied and spectral ranges where ethane has medium strength should be studied with caution.