The results confirm the presence of an underground reservoir of brine – water enriched with salt – remnants of a vast underground ocean that gradually froze.
“This elevates Ceres to the status of an ‘ocean world,’ noting that this category does not require the ocean to be global,” said Carol Raymond, planetary scientist and principal investigator at Dawn. “In the case of Ceres, we know that the reservoir of liquid is on a regional scale, but we cannot say for sure that it is global. However, what matters most is that there is liquid on a large scale. ”
Ceres is approximately 590 miles (950 km) in diameter. Scientists focused on the 57-mile-wide (92 km-wide) Occator Crater, formed by an impact about 22 million years ago in the northern hemisphere of Ceres. It has two clear areas – salt crusts left behind by the liquid that has percolated to the surface and evaporated.
The liquid, they concluded, came from a brine reservoir several hundred kilometers wide hidden about 40 kilometers below the surface, the impact creating fractures allowing the salt water to escape.
The research has been published in the journals Nature Astronomy, Nature Geoscience and Nature Communications.
Other bodies in the solar system beyond Earth where subterranean oceans are known or appear to exist include the moon of Jupiter Europa, the moon of Saturn Enceladus, the moon of Neptune Triton, and the dwarf planet Pluto.
Water is considered a key ingredient in life. Scientists want to assess whether Ceres was ever habitable by microbial life.
“There is major interest at this point,” said planetologist Julie Castillo of NASA’s Jet Propulsion Laboratory, “in quantifying the habitability potential of the deep brine tank, especially since it is cold and becomes quite rich in salts. ”
© Thomson Reuters 2020