There are six articles published in the journal “Science” that describe as many research on the dwarf planet Ceres. Using data collected by NASA’s Dawn space probe, various international groups of researchers examined a number of aspects of the geological activity that existed up to the recent past and even a temporary atmosphere.
Chris Russell, the Dawn mission’s principal investigator, led the team that discovered that Ceres may have an atmosphere, however tenuous and temporary. The analysis of the data collected by the GRaND (Gamma Ray and Neutron Detector) instrument showed that for about six days the solar wind’s electrons were accelerated to very high energies. This phenomenon could be caused by the interaction between the solar wind’s energetic particles and the molecules of Ceres’ atmosphere.
Ottaviano Ruesch of NASA’s Goddard Space Flight Center led the team that studied Ahuna Mons, a mountain of Ceres. It was already suggested that it was a cryovolcano and this was confirmed by this new research. The scientists compared this mountain with models of formation of volcanic domes, three-dimensional maps and geological elements of other places in the solar system. The result is that Ahuna Mons is most likely a cryovolcano erupting a liquid composed of water mixed with other materials instead of lava and it formed in recent times from a geological point of view.
Jean-Philippe Combe of the Bear Fight Institute, Winthrop, Washington, led the team that studied the Oxo crater, one of the most interesting and bright on Ceres. This research confirms the presence of water ice in Oxo crater, an intriguing fact because it was expected that the ice on the dwarf planet’s surface was unstable except at the poles. The measurements of the VIR instrument indicate the presence of water, meaning ice or hydrate materials. At the conditions existing today water ice can last on the surface only for a few decades at Oxo crater’s latitudes therefore the ice found must be emerged or be recently formed.
Harald Hiesinger of the Westfälische Wilhelms-Universität, Münster, Germany, led the team that analyzed the existing impact craters on Ceres. This allowed to better understand how the dwarf planet’s crust is composed: it was expected that it was icy but the variety in its morphology indicates a mixture of ice and rock. The heterogeneous distribution of the craters is a consequence of a variable composition in the different areas and suggests a complex geological evolution of Ceres.
Debra Buczkowski, of Johns Hopkins Applied Physics Laboratory led the team that analyzed the wide range of geological features on Ceres. This team studied the craters as well along with other features such as domes, lobed structures and linear flows. Phenomena such cryomagmatism and cryovolcanism were identified. The geomorphic analysis suggests the presence of faults beneath the surface.
Eleonora Ammannito of the University of California, Los Angeles led the team that analyzed the distribution of clay phyllosilicates minerals, which contain magnesium and ammonium, on Ceres’ surface. using the VIR instrument they determined their composition in different areas of the dwarf planet, which turned out to be quite uniform. Instead, the amount found varies greatly from area to area. These minerals are formed only in the presence of water so it’s possible that those present on the surface underwent changes caused by a large-scale process that included water.
Some research confirms previous hypotheses, others extend them and some offered new surprises. In recent days, the Dawn space probe began maneuvers that will bring it to a higher orbit in its extended mission to keep on collecting data on the dwarf planet Ceres.
