NASA scientists have discovered areas of Ceres that never see direct sunlight, making them likely locations for large deposits of frozen water on the dwarf planet.

The study, published in Geophysical Research Letters, shows that about one out of every 1,000 water molecules formed on the surface ends up in an ice deposit within one Cererian year (1,682 days).

"The conditions on Ceres are right for accumulating deposits of water ice," said Norbert Schorghofer, a Dawn guest investigator at the University of Hawaii at Manoa, in a statement. "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."

The research focused on the northern polar region of the dwarf planet, which is actually better illuminated than the southern hemisphere. Sophisticated computer models were used to estimate that about 1,800 square kilometers (695 square miles) were always in the shade.

"On Ceres, these regions act as cold traps down to relatively low latitudes," said Erwan Mazarico, a Dawn guest investigator at Goddard. "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."

According to the study, when it comes to ice deposits, Ceres is more similar to Mercury than to the moon. Both Mercury and Ceres have the same fraction of shaded areas in the northern hemisphere and have a similar efficiency in trapping water.

"While cold traps may provide surface deposits of water ice as have been seen at the moon and Mercury, Ceres may have been formed with a relatively greater reservoir of water," said Chris Russell, principal investigator of the Dawn mission, based at the University of California, Los Angeles. "Some observations indicate Ceres may be a volatile-rich world that is not dependent on current-day external sources."

According to recent studies, although Ceres is drier than previously thought, it is likely to have water ice in its interior and maybe even a subsurface ocean.