Mikhail Zolotov Arizona State University, Tempe, AZ, USA Email

Nature
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Nature
[1] Planetary science: Inside Ceres may be less icy and more salty (N&V) *IMAGES*
New analyses of data collected by NASA’s Dawn spacecraft during its visit to the dwarf planet Ceres, which lies in the asteroid belt between the orbits of Mars and Jupiter, are published in Nature and Nature Geoscience this week. The papers shed light on the composition of the dwarf planet’s mysterious bright spots and its subsurface, and suggest that some subsurface fluids existed, perhaps transiently, and may still exist.
The mostly dark surface of Ceres is dotted with more than 130 bright spots, with the most prominent situated within the Occator crater. Previous studies have suggested that these small bright areas may consist of large amounts of hydrated magnesium sulfate.
In the Nature paper, Maria Cristina De Sanctis and colleagues analyse data collected by the Visible and InfraRed Mapping Spectrometer on board the Dawn spacecraft at a distance of 1,400 kilometres from Ceres. They report that spectra of the bright material at Occator’s base are consistent with large amounts of sodium carbonates that are mixed with a dark component, small amounts of silicate minerals known as phyllosilicates, and ammonium carbonate or ammonium chloride. The authors suggest that these compounds were transported from within Ceres to the surface in an aqueous process after the impact crater was formed.
Writing in Nature Geoscience, Michael Bland and colleagues show that most of Ceres’ largest craters are too deep for the subsurface below the dwarf planet’s rocky outer layer to be mostly made up of ice. They conclude that the subsurface is more likely to be composed of only 30 to 40 per cent ice, with the remaining 60 to 70 percent a combination of rock and a strong, low-density material, perhaps made up of hydrated salts and clathrates.
Article details
DOI: 10.1038/nature18290
Corresponding Author:
Maria Cristina de Sanctis
INAF,Rome,Italy
Email: l: +39 0649934444
DOI: 10.1038/ngeo2743
Corresponding Author:
Michael Bland
US Geological Survey,Flagstaff,Arizona,United States
Email:
N&V Author for both papers

Mikhail Zolotov
Arizona State University, Tempe, AZ, USA
Email:

Please link to the article in online versions of your report (the URL will go live after the embargo ends):

Image 1

Caption: The topography of the dwarf planet Ceres. Numerous deep craters cover its surface, indicating that the subsurface contains less than 30% ice by volume. Orthographic projections are centered on 10 deg N, 145 deg. E (left) and 10 deg S, 325 deg E (right). Blue tones are low and red tones are high.
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Image 2

Caption: Dawn Visual and InfraRed Mapping Spectrometer
Credits: INAF/ASI/SELEX

Image 3

Caption: Prospective view of Occator crater on Ceres with superimposed the Dawn Imaging Spectrometer (VIR) acquisitions. Red colors mean high abundance of carbonates, grey colors mean low abundance.
Credit: INAF/ASI/NASA/DLR/MPS

Image 4