Normalised intensity profiles as a function of distance from the PSF centroid. The quasar 3C 454.3 is shown with a black solid line. The calibrator star profile is presented with a blue dashed line. The dashed-dotted magenta line indicates the Vesta PSF. The solid green line shows the mean of the nine Pluto observations (MM), while the filled grey area represents the measurement uncertainty. The faintest dust ring model detected at 3σ significance level is plotted with a dotted red line.