Some of Ceres’s bright spots covered with haze

While waiting for the Dawn spacecraft to spiral down to a closer look at the surface of Ceres, the situation with the bright spots has gotten more rather than less murky:


From the Nature article:

Haze on Ceres would be the first ever observed directly in the asteroid belt. In 2014, researchers using the European Space Agency’s Herschel Space Observatory reported seeing water vapour spraying off Ceres, which suggested that it was geologically active1. At least one-quarter of Ceres’s mass is water, a much greater proportion than seen in most asteroids.

Bright spots pepper Ceres’s surface, but the haze has so far been seen in only one location — a crater named Occator, which has a large bright area at its centre and several smaller spots nearby. Mission scientists have been trying to work out whether the bright spots are made of ice, evaporated salts or other minerals, or something else entirely.

Some team members had been leaning towards the salt explanation, but the discovery of haze suggests the presence of sublimating ice. “At noontime, if you look at a glancing angle, you can see what seems to be haze,” Russell says. “It comes back in a regular pattern.” The haze covers about half of the crater and stops at the rim.

2 thoughts on “Some of Ceres’s bright spots covered with haze”

  1. The ice verses salt debate could end in a draw! The brightest spot could be salt, and the remaining less bright spots with the haze-like “halos” around them could be ice. The haze-like “halos” around the less-bright spots could be a mixture of liquid water and electrically charged microscopic salt grains lifted off the brightest spot by some unknown process.

  2. Sounds reasonable. They should be able to do spectroscopy on the spots eventually and get the final answer.

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