Figure 22

Brightening comparison. Here we directly compare the spectra of the brightened surfaces from Yalaing Terra (i=40°, e=21°, ϕ=42°), Hetpet Regio (i=32°, e=55°, ϕ=45°), and Adiri (i=34°, e=15°, ϕ=20°). We exclude Concordia Regio due to the coarse VIMS spatial resultion there on T77 in which the brightened area fills less than a full pixel. Because the viewing geometries differ significantly, no accurate quantitative comparison is possible – particularly at short wavelengths. However the spectra agree with one another quite well, particularly at longer wavelengths where viewing geometry through the atmosphere plays a lesser role. Within the short-wavelength windows, 0.93 μ m, 1.08 μ m, and 1.28 μ m, atmospheric scattering leads to the apparent differences in I/F.