Foto van 558MB geeft bijna compleet beeld van dwergplaneet Ceres

[Reactie gewijzigd door MarcRvB op 23 juli 2024 13:51]

MarsCeresmannetjes hebben daar een basis

The team also released an enhanced color map of the surface of Ceres, highlighting the diversity of surface materials and their relationships to surface morphology.
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"Although impact processes dominate the surface geology on Ceres, we have identified specific color variations on the surface indicating material alterations that are due to a complex interaction of the impact process and the subsurface composition," Jaumann said. "Additionally, this gives evidence for a subsurface layer enriched in ice and volatiles."

So why is the crater shiny? In a paper published last December in Nature, scientists argued that the reflection may come from a magnesium sulfate called hexahydrite.

The idea is that Ceres has a salty layer of water ice just beneath its surface. At some point in the past, asteroids pummeled the dwarf planet, bringing that mixture to the surface. The water ice then evaporated away in the sun, leaving only the bright-colored hexahydrite behind. And because the rest of the planet is so dark, those bright spots stick out.

Nathues and colleagues, using images from Dawn's framing camera, suggest that these salt-rich areas were left behind when water-ice sublimated in the past. Impacts from asteroids would have unearthed the mixture of ice and salt, they say.

"The global nature of Ceres' bright spots suggests that this world has a subsurface layer that contains briny water-ice," Nathues said.