Publication Date:
2009-03-31
Description:
The dwarf planet Ceres is the largest object in the asteroid belt, and is generally thought to be a differentiated body composed primarily of silicate materials and water ice. Some remotely observed features, however, indicate that Ceres may instead have a composition more similar to that of the most common types of carbonaceous meteorite. In particular, Ceres has been shown to have a distinct infrared absorption feature centred at a wavelength of 3.06 m that is superimposed on a broader absorption from 2.8 to 3.7 m (refs5,8), which suggests the presence of OH- or H 2 O-bearing phases. The specific mineral composition of Ceres and its relationship to known meteorite mineral assemblages, however, remains uncertain. Here we show that the spectral features of Ceres can be attributed to the presence of the hydroxide brucite, magnesium carbonates and serpentines, a mineralogy consistent with the aqueous alteration of olivine-rich materials. We therefore suggest that the thermal and aqueous alteration history of Ceres is different from that recorded by carbonaceous meteorites, and that samples from Ceres are not represented in existing meteorite collections. © 2009 Macmillan Publishers Limited.
Print ISSN:
1752-0894
Electronic ISSN:
1752-0908
Topics:
Geosciences
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