New Study Suggests Past Water Flows on Vesta
Posted on January 22, 2015
A new study suggests that there were once short-lived water flows on Vesta. The above image shows curved gullies in the asteroid's Cornelia Crater. The protoplanet was once thought to be completely dry.
Scientists studying Vesta say the curved gullies are different from those formed by the flow of dry material. The narrow gullies are about 30 meters (100 feet) wide. They are about 900 meters long (half a mile) on average. A NASA JPL release says the current theory is the Vesta has ice patches on its surface (from comet impacts) and these patches melt and release water during subsequent impacts. The researchers say this ice would be too deeply buried in Vesta for it to have been detected by the Dawn spacecraft.
Jennifer Scully, postgraduate researcher at the University of California, Los Angeles, says in a statement, "Nobody expected to find evidence of water on Vesta. The surface is very cold and there is no atmosphere, so any water on the surface evaporates. However, Vesta is proving to be a very interesting and complex planetary body."
Scully says they are not suggesting there was a river-like flow of water on Vesta. The water flow on Vesta would have been more like a debris flow containing rocky particles.
You can view a larger image of the gully and fan-shaped deposit on Vesta here. A research paper on the Vesta gullies was published here in the journal, Earth and Planetary Science Letters.
NASA's Dawn spacecraft visited Vesta from 2011 to 2013. It is currently approaching the dwarf planet Ceres and will be captured into an orbit around the dwarf planet on March 6.