Scientists with NASA’s Dawn mission have identified, on the dwarf planet Ceres, permanently shadowed regions most of which likely have been cold enough to trap water ice for a billion years.
The findings suggest that ice deposits could exist in these regions even now.
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.
Permanently shadowed regions do not receive direct sunlight. They are typically located on crater floor or along a section of crater wall facing the pole.
The regions still receive indirect sunlight, but if the temperature stays below about minus minus 151 degrees Celsius, the permanently shadowed area is a cold trap: a good place for water ice to accumulate and remain stable.
Some observations indicate Ceres may be a volatile-rich world that is not dependent on current-day external sources.
The researchers found dozens of sizeable permanently shadowed regions across the northern hemisphere.