Scientists at the European Planetary Science Conference (EPSC, 2015) in Nantes, France are busy with the mysterious crater structures and fascinating views of the multifaceted dwarf planet Ceres. The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) is involved in the NASA Dawn mission and, among other things, is responsible for the mapping and naming of regions and striking surface features, in collaboration with the International Astronomical Union (IAU).
Ceres continues to fascinate researchers; in particular, the dwarf planet’s surface repeatedly raises new questions. “We are working hard to understand how such a small body was able to develop such a fascinating topography,” says Ralf Jaumann from the DLR Institute of Planetary Research in Berlin-Adlershof. Today a new, colour-coded, topographic map was published that contains more than a dozen new names for the surface features on Ceres, recently approved by the IAU. These are, as usual, inspired by agricultural spirits, fertility deities and harvest feasts from different parts of the world. The new names include, for example, ‘Jaja’, the Abkhaz harvest goddess, and ‘Ernutet’, the cobra-headed Egyptian deity of harvest. A 20-kilometre-diameter mountain, located near Ceres’ north pole is now ‘Ysolo Mons’ – named after an Albanian feast marking the first day of aubergine harvesting.
False colours, true knowledge
The Ceres map also clearly highlights, for the first time, differences in the surface composition in false colour in a global context. The variations on Ceres, however, are more subtle than on Vesta, which was explored by the Dawn spacecraft between 2011-2013. Newly added to the map are colour-coded images of the spectacular Occator Crater, with its steep slopes and bright spots – its origin and surface composition have puzzled the Dawn science team for months. A mysterious, cone-shaped, six-kilometre-high mountain has been observed, whose exceptionally steep and uniform structure is sure to puzzle scientists further. Overall, 14 new craters have been detected and incorporated into the map.
A surprising observation came from Dawn’s Gamma Radiation and Neutron Spectrometer: the instrument registered three bursts of energetic electrons, which could possibly be the result of an interaction between Ceres and incoming solar radiation. “We are totally surprised by Ceres,” admits Jaumann. “We did not think that there could still be activity on the surface today.” This observation will be actively researched, as it could play a significant role in achieving an integrated picture of the dwarf planet.
Orbiter during descent
At present, the Dawn spacecraft is orbiting Ceres at an altitude of 1470 kilometres, its ‘HAMO’ (High-Altitude Mapping Orbit). In this mission phase, the entire surface of the dwarf planet will be recorded up to six times. From October to December, Dawn will descend to its lowest orbit ‘LAMO’, at an altitude of 375 kilometres. The spacecraft will remain at this altitude and continue to scan the dwarf planet and acquire data. The Dawn mission will continue until at least the middle of next year.
The Dawn mission to Vesta and Ceres is managed by NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, which is a division of the California Institute of Technology, for NASA’s Science Mission Directorate in Washington DC. The University of California, Los Angeles, is responsible for overall Dawn mission science. The camera system on the spacecraft was developed and built under the leadership of the Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germany, with significant contributions from the German Aerospace Center (DLR) Institute of Planetary Research in Berlin and the Institute of Computer and Communication Network Engineering in Braunschweig. The Framing Camera project is funded by the Max Planck Society, DLR, and NASA/JPL.