New images of Ceres’ Occator Crater, home to the brightest of the bright spots detected by the Dawn spacecraft during its visit to the dwarf planet in March 2015, and an enhanced color map of the surface were among the new findings first unveiled by NASA on Tuesday.
Speaking at the 47th annual Lunar and Planetary Science Conference in The Woodlands, Texas, officials from the US space agency released images of the 57 mile (92 km) long, 2.5 mile (4 km) deep Occator Crater taken at a distance of 240 miles (385 km) above the dwarf planet’s surface.
The new images reveal that the center of the crater is home to a dome in a smooth-walled pit, and that multiple linear features and fractures crisscross the top and sides of this feature. The dome is also surrounded by several fractures, and some prominent ones also run through the small, bright areas located within the crater itself, the researchers explained.
“Before Dawn began its intensive observations of Ceres last year, Occator Crater looked to be one large bright area. Now, with the latest close views, we can see complex features that provide new mysteries to investigate,” Ralf Jaumann, a planetary scientist and Dawn co-investigator at the German Aerospace Center (DLR) in Berlin, said in a statement.
According to Jaumann, the “intricate geometry of the crater interior” suggests that the region had been the site of geologic activity at some point in “the recent past.” However, he added, “we will need to complete detailed geologic mapping of the crater” to find out exactly how it formed.
Here’s a video explaining more about recent findings about Ceres:
Possible volatile minerals, crater containing water also discovered
In addition, NASA released an enhanced color map of the dwarf planet’s surface on Tuesday – a map which revealed that Ceres does not have as many large impact basins as scientists originally expected. However, predictions of smaller impact craters did turn out to be generally correct, and the new map revealed the diversity of surface materials and the morphology of the terrain.
Blue materials depicted in the color map is associated to features that appear to be very young, including flows, smooth plains and mountains, Jaumann and his colleagues explained. They also identified specific color variations indicating material alterations believed to be the result of the interaction between impacts and the composition of Ceres’ subsurface. These findings, NASA said, also provide evidence that the subsurface is rich in ice and volatile minerals.
Dawn’s Gamma Ray and Neutron Detector (GRaND) is also providing data that could result in the discovery of subsurface ice on the dwarf planet. The instrument, which began acquiring its primary data set in December, searches for neutrons and gamma rays produced by the interaction of cosmic rays with surface materials, and should be able to determine the chemical makeup of the uppermost layer of the regolith, the agency noted.
While the spacecraft was in its lowest-altitude orbit, GRaND detected a higher number of neutrons at the equator than at the poles, which suggests that higher latitudes have a higher concentration of hydrogen, one of the principle components of water. This would appear to suggest that there may be water ice close to the surface in the polar regions of Ceres. More analysis is needed before the presence of water ice can be confirmed, however, cautioned Tom Prettyman, GRaND from the Planetary Science Institute in Tucson, Arizona.
NASA also revealed that data collected by Dawn has found evidence that the region known as Haulani Crater revealed that the subsurface of this region appeared to have a different chemical composition than the majority of the dwarf planet, and that there may be water present at Oxo Crater, a six mile (9 km) wide feature located in the northern hemisphere. It is unknown at this time is that water is bound up in minerals or exists in the form of ice.
Image credit: NASA