Ceres bright spots could be active icy plumes or other active geological features

A pair of bright spots glimmering inside an impact crater on the dwarf planet Ceres, mystifying scientists, could be coming from some kind of icy plume or other active geological feature.

New images from NASA’s Dawn spacecraft show the spots, known as ‘feature number 5’, at changing angles as the dwarf planet rotates in and out of sunlight. The pictures reveal the spots even when they appear near the edge of Ceres, when the sides of the impact crater would normally block the view of anything confined to the bottom. That something is visible at all in this circumstance suggests that the feature must rise relatively high above the surface.

“What is amazing is that you can see the feature while the rim is still in the line of sight,” said Andreas Nathues, a planetary scientist at the Max Planck Institute for Solar System Research in Göttingen, Germany. Nathues, who leads the team for one of the Dawn cameras, revealed the images on 17 March at the Lunar and Planetary Science Conference in The Woodlands, Texas.

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. The Dawn spacecraft captured this image of Ceres’ twin bright spots on 19 February.

Tip of the ice plume

At dawn on Ceres, feature number 5 appears bright. By dusk, it seems to fade. That could mean that sunlight plays an important part — for instance, by heating up ice just beneath the surface and causing it to blast off some kind of plume or other feature.

Ceres is believed to be at least one-quarter ice — more so than most asteroids. Dawn’s goal is to work out where that ice resides and what role it has in shaping the dwarf planet’s surface. One idea is that the ice is blanketed by a very thin layer of soil. The ice may occasionally squirt up in towering ‘cryovolcanoes’, thanks to internal pressures in the asteroid.

SOURCES- Journal Nature

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