Ceres is too small and lacks its own for-self-only orbit (cleared neighborhood around its orbit) for it to be classified as a planet, but those shortcomings don’t make it a less interesting world. From the get-go, Ceres is worthy of the humanity’s attention for one conspicuous reason: it is the largest of the rocks in the asteroid belt.
In addition, it is also the only rock in the belt–in between the orbits of Mars and Jupiter–that is nearly spherical in shape, thus scientists call it a “dwarf planet” like the former 9th planet, Pluto. That said, it doesn’t need to become a planet to capture the fascination of scientists working at NASA.
In 2015, the space agency’s mission for Ceres, the Dawn spacecraft, entered the rock’s orbit, making it the first man-made spacecraft to reach and orbit the largest asteroid of the belt. And after more than a year of staying in sync with Ceres, the Dawn delivered enough data back to Earth which allow scientists to map and identify the dwarf planet’s permanently shadowed regions. Such regions may let Ceres develop deposits of ice.
Dawn guest investigator Norbert Schorghofer of the University of Hawaii at Manoa has spoken with the NASA press about the activity, and he revealed that conditions there are capable of accumulating deposits of water ice. Plus, Ceres has enough mass to keep the water molecules intact within those shadowed regions. Those regions, he has revealed, were identified as extremely cold places, which he said are much colder than those found on the moon or Mercury.
Regions at Ceres that are permanently shadowed–those that can keep surface ice–were identified using the data from Dawn, combined with sophisticated computer modeling of illumination.
Regions there which are permanently shadowed essentially do not receive direct sunlight; NASA said they are typically located on crater floor–or, along a section of the crater wall facing toward the pole. The agency clarified that such regions still receive indirect sunlight, but if the temperature of the place stays below about -151 degrees Celsius, or -240 Fahrenheit, then the area is a cold trap which could accumulate water ice, and such deposits remain stable.
Cold traps on the dwarf planet were predicted before, and only at this time that scientists have identified their existence there.
Through a study, Schorghofer and colleagues revealed how they were able to map and identify the cold traps in Ceres. First, the team has studied its northern hemisphere, which they say was better illuminated than the south. Second, images from Dawn’s cameras were combined to recreate the world’s shape which shows its craters, plains and other terrains in three dimensions. Then, a computer model developed at NASA was used to determine the places that receive direct sunlight, in addition to finding how much solar radiation reaches the surface.
They also have identified using the same model the change in conditions over the course of a year on the dwarf planet.
The team has found dozens of fairly large, permanently shadowed regions across the world’s northern hemisphere; the largest they say is inside a 10-mile wide crater located about 40 miles from the north pole.
Overall, they have found that permanently shadowed regions there occupy about 695 square miles, which if compared to the total surface area of the northern hemisphere, is just 1 percent.
The situation on Ceres, NASA said, is more similar to that on Mercury (which is the nearest planet to the sun), than the moon, Earth’s lone natural satellite. Mercury too has permanently shadowed regions; and based on trapping efficiency–or the ability to accumulate water ice–both are comparable, they added.