Water Vapor Spotted On Dwarf Planet Ceres

Lee Rannals for redOrbit.com – Your Universe Online

Water vapor has been discovered around the dwarf planet Ceres thanks to new data from the Herschel Space Observatory.

Ceres is the largest object in the asteroid belt and sits between the orbits of Mars and Jupiter. Scientists believe that Ceres is layered with a rocky core and icy outer mantle, which has significant implications for our understanding of the evolution of the Solar System. The latest data from Herschel helps support the argument that asteroid and comet impacts helped deliver water to planets like Earth and Mars.

Scientists using the HIFI instrument on Herschel collected data on Ceres which points to water vapor being emitted from the dwarf planet.

“This is the first time that water has been detected in the asteroid belt, and provides proof that Ceres has an icy surface and an atmosphere,” said Michael Küppers of ESA’s European Space Astronomy Centre in Spain, lead author of the paper published in journal Nature.

Herschel did not, however, spot water vapor every time scientists looked for it. The telescope peered at Ceres four different times, one of which showed no signature of water vapor. Scientists believe this happened because when Ceres’ orbit is at its closet point to the sun, a portion of its icy surface becomes warm enough to cause water vapor to escape in plumes at a rate of 13 pounds per second. However, when the dwarf planet is in the colder parts of its orbit no water is escaping.

Two of the water breathing regions are about 5 percent darker than the average spot on Ceres, enabling them to absorb more sunlight to heat up the ice to turn it into water vapor.

“Herschel’s discovery of water vapor outgassing from Ceres gives us new information on how water is distributed in the Solar System. Since Ceres constitutes about one fifth of the total mass of asteroid belt, this finding is important not only for the study of small Solar System bodies in general, but also for learning more about the origin of water on Earth,” Göran Pilbratt, ESA’s Herschel Project Scientist, said in a statement.

More intel about Ceres will be uncovered when NASA’s Dawn mission arrives at the dwarf planet next year. Dawn is scheduled to arrive at Ceres in the spring of 2015.

“We’ve got a spacecraft on the way to Ceres, so we don’t have to wait long before getting more context on this intriguing result, right from the source itself,” Carol Raymond, the deputy principal investigator for Dawn at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement. “Dawn will map the geology and chemistry of the surface in high resolution, revealing the processes that drive the outgassing activity.”

Dawn will allow scientists to look at the dark spots on Ceres in more detail, allowing them to find out more about what is happening with the dwarf planet’s icy outer mantle. The spacecraft isn’t a newbie to research either, before it made its way towards Ceres, Dawn spent over a year orbiting the large asteroid Vesta.