Monday, January 18, 2016

Scientists Find Brine Deposits Source of Ceres’ Bright Spots

One of the most intriguing features on Ceres, Occator crater, is home to the brightest areas on Ceres. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Bright spots seen by NASA’s Dawn spacecraft on the surface of dwarf planet Ceres are likely salt deposits. Ceres has more than 130 bright areas, and most of them are associated with impact craters. Observations from Dawn’s Framing Camera suggest the occurrence of salts originating from Ceres’ interior. These salts are consistent with a type called magnesium sulfate according to a Nature paper on which Planetary Science Institute’s (PSI) Lucille Le Corre, Vishnu Reddy, Jian-Yang Li, David O’Brien and Mark Sykes are co-authors.

“We reviewed three possible analogs for the bright spots (ice, clays and salts),” said Le Corre, a PSI Research Scientist. “Salts seem to fit the bill and are the best possible explanation of what we see on the surface of Ceres.”

Le Corre and colleagues, using images from Dawn's framing camera, suggest that these salt-rich areas were left behind when water-ice sublimated in the past. Impacts from asteroids would have unearthed the mixture of ice and salt.

“The location of some bright spots also coincide with places where water vapor was detected by other spacecraft,” said Reddy, a PSI Research Scientist. “This gives us confidence that the bright spots are likely salt deposits left over by sublimating salty water.”

Dawn is the first mission to visit a dwarf planet, and the first mission outside the Earth-moon system to orbit two distinct solar system targets. After orbiting Vesta for 14 months in 2011 and 2012, it arrived at Ceres on March 6, 2015.

Dawn's mission is managed by the Jet Propulsion Laboratory for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.

Credit: psi.edu

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