Dwarf planet Ceres is flush with ice, NASA studies show

The dwarf planet Ceres, an enigmatic rocky body inhabiting the main asteroid belt between Mars and Jupiter, is rich with ice just beneath its dark surface, scientists said on Thursday in research that may shed light on the early history of the solar system.

The discovery, reported in a pair of studies published in the journals Science and Nature Astronomy, could bolster fledgling commercial endeavors to mine asteroids for water and other resources for robotic and eventual human expeditions beyond the moon.

NASA's Dawn spacecraft has been orbiting Ceres, the largest of thousands of rocky bodies located in the main asteroid belt, since March 2015 following 14-month study of Vesta, the second-largest object in the asteroid belt.

The studies show that Ceres is about 10 percent water, now frozen into ice, according to physicist Thomas Prettyman of the Planetary Science Institute in Tucson, Arizona, one of the researchers.

Examining the makeup of solar system objects like Ceres provides insight into how the solar system formed. Compared to dry Vesta, Ceres is more like Enceladus and Europa, icy moons of the giant gas planets Saturn and Jupiter respectively, than Earth and the other terrestrial planets Mercury, Venus and Mars, Prettyman added.

Scientists are debating if Ceres hides a briny liquid ocean, a prospect that may put the dwarf planet on the growing list of worlds beyond the solar system that may be suitable for life, said Dawn deputy lead scientist Carol Raymond of NASA's Jet Propulsion Laboratory in Pasadena, California.

"By finding bodies that were water-rich in the distant past, we can discover clues as to where life may have existed in the early solar system," Raymond said in a statement.

The finding strengthens the case for the presence of near-surface water ice on other bodies in the main asteroid belt, Prettyman said.

Information collected by Dawn showed that Ceres, unlike Vesta, has been using water to create minerals. Scientists combine mineralogical data with computer models to learn about its interior.

"Liquid water had to be in the interior of Ceres in order for us to see what's on the surface," Prettyman told a news conference at the American Geophysical Union conference in San Francisco.

(Reporting by Irene Klotz; Editing by Will Dunham)