The researchers used the Herschel Space Observatory’s spectrometer to look for signals of water. Clouds of water vapor around Ceres absorbed the heat that radiates from the dwarf planet, which Herschel’s instrument detected. The team found that Ceres produces about 2×10^26 molecules, or 13 lbs. (6 kilograms), of water vapor per second from its surface.
One possible source of the water is icy volcanism. “It is like volcanism in that hot material from the interior is ‘spat out’ to the surface,” Küppers said — much like a geyser. But these icy volcanoes eject water vapor instead of molten rock, he said.
Another possibility is that ice near the surface of Ceres sublimes, or goes directly from a solid to a gas, dragging with it dust from the surface and exposing more ice. A similar process occurs on comets.
“I personally consider cometary-style sublimation the most likely source, because I find it difficult to maintain the internal heat over the age of the solar system to maintain volcanoes,” Küppers said, but he added that more studies were needed.
Water Found on Dwarf Planet Ceres, May Erupt from Ice Volcanoes
Scientists think Ceres may have an ocean and possibly an atmosphere.
With temperature highs of minus 38 degrees C (minus 37 F), water at the surface of Ceres would sublimate, potentially creating a thin atmosphere.
Ceres: The Smallest and Closest Dwarf Planet
Here is what scientists think is happening: when Ceres swings through the part of its orbit that is closer to the sun, a portion of its icy surface becomes warm enough to cause water vapor to escape in plumes at a rate of about 6 kilograms (13 pounds) per second. When Ceres is in the colder part of its orbit, no water escapes.
The strength of the signal also varied over hours, weeks and months, because of the water vapor plumes rotating in and out of Herschel’s views as the object spun on its axis. This enabled the scientists to localize the source of water to two darker spots on the surface of Ceres, previously seen by NASA’s Hubble Space Telescope and ground-based telescopes. The dark spots might be more likely to outgas because dark material warms faster than light material. When the Dawn spacecraft arrives at Ceres, it will be able to investigate these features.
The results are somewhat unexpected because comets, the icier cousins of asteroids, are known typically to sprout jets and plumes, while objects in the asteroid belt are not.
Herschel Telescope Detects Water on Dwarf Planet
Was and is water vapour coming from the surfaces a form of electron spluttering similar to that found on active asteroids (comets) and the Moon?
The Electric Universe theory would seem to suggest that the water vapour is nothing to do with sublimation in the freezing cold of space but due to the difference in the electrical charged nature of the rocky body and the electric charged solar wind (plasma).
Will Ceres be found to have a rocky surface?