27.02.2022

The finding comes from a fresh analysis of old data from NASA's Dawn spacecraft, which finished its mission in 2018.

White deposits associated with Urvara crater on Ceres suggest cryovolcanic activity. (Image credit: MPS, based on data from the Dawn mission: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

Ceres might be spewing cryovolcanoes in yet another spot on the dwarf planet's surface. 

Close-up pictures from NASA's Dawn mission that orbited Ceres between 2015 and 2018 revealed salt deposits in a crater known as Urvara, spotted for the first time in a new study. The salt deposits may be associated with icy volcanoes, the research team says, whose brine rose to the surface over time. 

Given there are multiple zones on Ceres with salt deposits, the implication is there might be a source of salt underneath the asteroid's surface, such as a possible saline ocean. (The salts, however, might have come from the impact that formed Urvara 250 million years ago instead.)

The larger implication is what water could mean on a relatively small world that is less than 300 miles (482 kilometers) in diameter, especially in terms of understanding the formation of Ceres and larger dwarf planets like it. This is far from the first study to suggest a possible global ocean hidden inside Ceres and adds to years of speculation about how so much liquid water could be possible in a tiny world far out in the solar system. 

"The large impact structures on Ceres give us access to the deeper layers of the dwarf planet," lead author Andreas Nathues, a scientist at the Max Planck Institute for Solar System Research (MPS) in Göttingen, Germany, said in a statement.

Natheus pointed out that the topography and composition of the craters seems to indicate "complex and long-lasting geological processes that have altered the dwarf planet's surface." The 105-mile-wide (170 km) Urvara is an example of this; the asteroid that formed the crater 250 million years ago excavated material from as deep as 31 miles (50 km) below the surface. 

The team mostly relied upon images taken by Dawn during its extended mission, which brought the spacecraft to within just 22 miles (35 km) of the surface to take high-resolution photography. MPS' two Dawn Framing Cameras obtained the data that was used in the study.

This close-up photo of the Vinalia Faculae in Ceres' Occator Crater was captured by NASA's Dawn spacecraft in its second extended mission, from an altitude as low as 21 miles (34 kilometers). (Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

The images showed a "geologically distinctly diverse landscape" within Urvara, the researchers said in the release, including terraced crater walls, a large mountain range, sharp cliffs and most importantly for the cryovolcano argument, bright material that looks a lot like the salts found in the more famous Occator crater. 

The salts are notable not only for their potential for cryovolcanoes, but also because they are close to organic compounds, meaning the carbon-containing building blocks of life as we know it. It's the first time salt deposits and organic compounds were found combined on the surface. They were particularly concentrated on a slope west of the central mountains, researchers said.

This NASA map shows the location of major craters on the surface of the dwarf planet Ceres in the asteroid belt. (Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

The organics find has "important implications for the overall geologic history of Ceres as well as potential links to astrobiology and habitability," noted scientist Guneshwar Thangjam, who is at the National Institute of Science Education and Research in Bhubaneswar, India. 

The team will compare the Urvara organics to those found in another crater, Ernutet, to better answer those astrobiology and habitability links, Thangjam added. 

A study based on the research was published Tuesday (Feb. 22) in Nature.

Quelle: SC