NASA: Dawn Maps Ceres Crater Where Water Ice Accumulates
Extending Dawn's mission to Ceres proved to be worth it as scientists, with the help of the spacecraft, identified shadowed regions where water ice accumulates on the dwarf planet.
Some areas in Ceres, located in the asteroid belt, are permanently "shadowed" and scientists have long been suggesting that the region is cold enough to trap water ice for billions of years. "The conditions on Ceres are right for accumulating deposits of water ice," Norbert Schorghofer, a Dawn guest investigator at the University of Hawaii said in a press release. "Ceres has just enough mass to hold on to water molecules, and the permanently shadowed regions we identified are extremely cold -- colder than most that exist on the moon or Mercury," Schorghofer added.
The regions where water ice is believed to accumulate don't receive direct sunlight. These are mostly found on crater floors or in hidden sections of the crater wall facing the pole. NASA believes that if the temperature stays below minus 240 degrees, then those places are a good area to find water ice collected for years. It is the first time these "cold traps" was distinctly identified.
In the study, images of Ceres' northern hemisphere, the more illuminated region, were combined to render the dwarf planet's shape in 3D. Dozens of permanently shadowed regions were discovered; the largest is inside a 10-mile-wide crater less than 40 miles from the north pole.
A total of 695 square miles of shadowed region was identified, less than one percent of the total surface area of Ceres' northern hemisphere. "On Ceres, these regions act as cold traps down to relatively low latitudes," Erwan Mazarico, Dawn guest investigator said in a statement. "On the moon and Mercury, only the permanently shadowed regions very close to the poles get cold enough for ice to be stable on the surface," Mazarico added.
Dawn recently completed its mission on the dwarf planet Ceres on June 30. Scientists proposed that Dawn utilized its remaining fuel by performing a flyby in another mysteries body, but NASA's Planetary Mission Senior Review Panel decided to extend Dawn's mission in Ceres instead.