The motions of the bright spots on Ceres

This artist’s impression video is based on a detailed map of the surface compiled from images taken from NASA’s Dawn spacecraft in orbit around the dwarf planet Ceres. It shows the very bright patches of material in the crater Occator and elsewhere. New observations using the HARPS spectrograph on the ESO 3.6-metre telescope at La Silla in Chile have revealed unexpected daily changes on these spots, suggesting that they change under the influence of sunlight as Ceres rotates.

This illustration shows how the features in the spectrum of the light reflected from the bright spots is alternately red and blue shifted slightly compared to the average light of Ceres as it rotates. This very subtle effect has been measured from the ground using the HARPS spectrograph on the ESO 3.6-metre telescope at La Silla in Chile. The effect has been greatly exaggerated to make it visible and excludes the much brighter light coming from the rest of the disc of Ceres.