Close-up view of the lower panel of Fig. 10. The width of each coloured box is Triton’s surface temperature (T_surf), as estimated by the various authors mentioned just above the boxes (see text for details). The heights of the boxes are the range of surface pressures, p_surf, using the ideal gas law , where is the surface molecular nitrogen density derived from our inversion of the RSS data (see text). We note that all the boxes intersect the vapour pressure equilibrium, which is plotted as a dotted line. This shows that the RSS surface density and the estimated surface temperatures are mutually consistent with a pressure being controlled by the N2 ice sublimation.