NASA's Dawn spacecraft has taken the sharpest-ever photos of Ceres, just a month before slipping into orbit around the mysterious dwarf planet.

Dawn captured thenew Ceres imagesWednesday (Feb. 4), when the probe was 90,000 miles (145,000 kilometers) from the dwarf planet, the largest object in the main asteroid belt between Mars and Jupiter.

On the night of March 5, Dawn will become the first spacecraft ever to orbit Ceres and the first to circle two different solar system bodies beyond Earth. (Dawn orbited the protoplanet Vesta, the asteroid belt's second-largest denizen, from July 2011 through September 2012.) [Amazing Photos of Dwarf Planet Ceres]

"It's very exciting," Dawn mission director and chief engineer Marc Rayman, who's based at NASA's Jet Propulsion Laboratory in Pasadena, California, said of Dawn's impending arrival atCeres. "This is a truly unique world, something that we've never seen before."

The 590-mile-wide (950 km) Ceres was discovered by Italian astronomer Giuseppe Piazzi in 1801. It's the only dwarf planet in the asteroid belt, and contains about 30 percent of the belt's total mass. (For what it's worth,Vestaharbors about 8 percent of the asteroid belt's mass.)

Despite Ceres' proximity (relative to otherdwarf planets such as Pluto and Eris, anyway), scientists don't know much about the rocky world. But they think it contains a great deal of water, mostly in the form of ice. Indeed, Ceres may be about 30 percent water by mass, Rayman said.

Ceres could even harbor lakes or oceans of liquid water beneath its frigid surface. Furthermore, in early 2014, researchers analyzing data gathered by Europe's Herschel Space Observatory announced that they had spotted a tiny plume ofwater vapor emanating from Ceres. The detection raised the possibility that internal heat drives cryovolcanism on the dwarf planet, as it does on Saturn's moon's Enceladus. (It's also possible that the "geyser" was caused by a meteorite impact, which exposed subsurface ice that quickly sublimated into space, researchers said).

The interior of Ceres may thus possess liquid water and an energy source two key criteria required for life as we know it to exist.

Dawn is not equipped to search for signs of life. But the probe which is carrying a camera, a visible and infrared mapping spectrometer and a gamma ray and neutron spectrometer will give scientists great up-close looks at Ceres' surface, which in turn could shed light on what's happening down below. [6 Most Likely Places for Alien Life in the Solar System]

For example, Dawn may see chemical signs of interactions between subsurface water, if it exists, and the surface, Rayman said.

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NASA probe snaps amazing image of Ceres