A NASA spacecraft en-route to the largest body in the asteroid belt between Mars and Jupiter returned its sharpest images yet of its target, the dwarf planet Ceres.
The Dawn spacecraft, which previously spent 14 months exploring Vesta, a protoplanet and second-largest body in the main asteroid belt, is due to put itself into orbit around Ceres on March 6.
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On Tuesday, with less than 150 million miles to go, NASA released new images of Ceres taken by Dawn, which now has a sharper view of its target than the Hubble Space Telescope.
The pictures, taken on Sunday, show several dark areas in Ceres' southern hemisphere that may be craters, said Carol Raymond, deputy principal investigator for the mission.
"Ceres is showing us tantalizing features that are whetting our appetite for the detailed exploration to come," Raymond said in a NASA press release accompanying the images.
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With a diameter of about 590 miles, Ceres is the largest body in the main asteroid belt. Scientists suspect it had an underground ocean at some point in its past and may still have liquid water beneath its icy surface.
Analysis of early images also suggest Ceres might have at least one large extended structure.
"If it is tectonic, it should provide insight into the interior processes of this small planet," Mark Sykes, with the Planetary Science Institute and a mission co-investigator, said in a statement.
Discovered in 1801, Ceres was once known as a planet, then reclassified as an asteroid. It was recast as a dwarf planet, like Pluto, in 2006.