Traces of Hydrated Minerals on Asteroid Vesta

A new finding by NASA's Dawn spacecraft is that the giant asteroid Vesta has its own version of ring around the collar.

Vesta is noted for being the most massive member of the main asteroid belt.  The researchers found this data about 130 miles above earth surface. It was Sept 4 that Dawn left Vesta and is now heading to the dwarf planets.

There were observations made from the low altitude mapping orbit of the dawn mission show that volatile or easily evaporated materials have colored vesta's surface in a broad swath around its equator.

Though Dawn did not find the actual water ice at Vesta but showed the presence of some hydrated minerals delivered by meteorites and dust that is evident in the Vesta's geology.

There were two papers on this observation. One paper was led by Thomas Prettyman , the lead scientist for Dawn's gamma ray and neutron detector (GRaND) at the Planetary Science Institute in Tucson, Ariz.

He talks of how hydrogen was traced by Dawn and is thought to be in the form of hydroxyl or water bound to minerals in Vesta's surface.

"The source of the hydrogen within Vesta's surface appears to be hydrated minerals delivered by carbon-rich space rocks that collided with Vesta at speeds slow enough to preserve their volatile content," said Prettyman.

A complementary paper was led by Brett Denevi, a Dawn participating scientist based at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., who describes the presence of pitted terrain that is triggered due to the release of the volatiles.

Scientists thought it might be possible for water ice to survive near the surface around the giant asteroid's poles.  Vesta has no permanently shadowed polar regions where ice might survive.  

"The pits look just like features seen on Mars, but while water was common on Mars, it was totally unexpected on Vesta in these high abundances," said Denevi. "These results provide evidence that not only were hydrated materials present, but they played an important role in shaping the asteroid's geology and the surface we see today."