Surface water-ice deposits in the northern shadowed regions of Ceres

• Published in: Nature astronomy Vol. 1; no. 1
• Main Authors: Platz, T., Nathues, A., Schorghofer, N., Preusker, F., Mazarico, E., Schröder, S. E., Byrne, S., Kneissl, T., Schmedemann, N., Combe, J.-P., Schäfer, M., Thangjam, G. S., Hoffmann, M., Gutierrez-Marques, P., Landis, M. E., Dietrich, W., Ripken, J., Matz, K.-D., Russell, C. T.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-01-2017; Nature Publishing Group
• Subjects: 639/33/445/125; 704/445/215; 704/445/848; Astronomy; Astrophysics and Cosmology; Ice; letter; Mercury; Physics; Physics and Astronomy; Surface water; Water content; Water vapor
• ISSN: 2397-3366; 2397-3366
• DOI: 10.1038/s41550-016-0007

Ceres, a dwarf planet located in the main asteroid belt, has a low bulk density
1
, and models predict that a substantial amount of water ice is present in its mantle and outer shell
2
–
4
. The Herschel telescope and the Dawn spacecraft
5
have observed the release of water vapour from Ceres
6
,
7
, and exposed water ice has been detected by Dawn on its surface at mid-latitudes
8
. Water molecules from endogenic and exogenic sources can also be cold-trapped in permanent shadows at high latitudes
9
–
11
, as happens on the Moon
12
,
13
and Mercury
14
,
15
. Here we present the first image-based survey of Ceres’s northern permanent shadows and report the discovery of bright deposits in cold traps. We identify a minimum of 634 permanently shadowed craters. Bright deposits are detected on the floors of just 10 of these craters in multi-scattered light. We spectroscopically identify one of the bright deposits as water ice. This detection strengthens the evidence that permanently shadowed areas have preserved water ice on airless planetary bodies.
Bright deposits, at least one of which is made up of water ice, are detected in the permanent shadows of 10 craters in the northern polar area of the dwarf planet Ceres. This means that Ceres traps water ice at high latitudes, like the Moon and Mercury.