New observations offer evidence that there's water everywhere on dwarf planet Ceres. Scientists revealed that data from NASA's Dawn spacecraft shows water ice is ubiquitous in the biggest asteroid in the Solar System
Vast Stores Of Water Ice
Scientists have long theorized that the surface and subsurface of Ceres has vast stores of water ice. A model developed in 1989 suggested the presence of layers of ice measuring between 3 to 330 feet in the surface and subsurface of this extraterrestrial world.
The model was created using data gathered from ground-based telescopes, but recently gathered data suggest that estimates based on this decades-old model was not far off.
Researchers used images captured by Dawn to analyze the craters in the northern polar region of the asteroid and identified regions of perpetual shadow in more than 600 craters. Of these craters, 10 had bright spots that reflect high levels of sunlight. Wavelengths of light that were reflected off these patches revealed the reflective surfaces contain water ice.
"We spectroscopically identify one of the bright deposits as water ice. This detection strengthens the evidence that permanently shadowed areas have preserved water ice on airless planetary bodies," study researcher Thomas Platz, from Max Planck Institute for Solar System Research, and colleagues reported in Nature Astronomy on Dec. 15.
Ceres Was Once An Ocean World
Although water on Ceres is frozen as ice that fill the asteroid's pore spaces or locked inside hydrated materials at the surface, the dwarf planet was once an ocean world. Early in this its history, heat from the formation of the Solar System likely warmed Ceres inside, allowing water to churn and flow and helped separate this world into layers of rock and ice.
Researchers were already aware that Ceres, which is technically both an asteroid and a dwarf planet, was rich in water based on its estimated density, light reflected off the hydrated minerals on the surface, and water spotted steaming from it. Scientists, however, did not know exactly the amount of water present on Ceres until Dawn's rendezvous with the dwarf planet in March 2015.
Dawn studies chemical elements by analyzing the gamma rays and neutrons that are reflected off the asteroid belt object as it is being bombarded by cosmic rays.
Thomas Prettyman, from the Planetary Science Institute in Tucson, Arizona, and colleagues came up with a map of the asteroid's hydrogen that appears in water ice and hydrated minerals.
They found that hydrogen levels were highest in the middle to high latitudes, and the greatest concentration of up to 30 percent water can be found at the north pole. Frozen water has dried out around the equator, but it abounds at the north pole.
Pretty and colleagues published their findings in Science on Dec. 15.