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

Ceres, a dwarf planet located in the main asteroid belt, has a low bulk density1, and models predict that a substantial amount of water ice is present in its mantle and outer shell2–4. The

Herschel telescope and the Dawn spacecraft5 have observed the release of water vapour from Ceres6,7, and exposed water ice has been detected by Dawn on its surface at mid-latitudes8. Water

molecules from endogenic and exogenic sources can also be cold-trapped in permanent shadows at high latitudes9–11, as happens on the Moon12,13 and Mercury14,15. 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.

We acknowledge the outstanding work of the Dawn design, engineering and operations team. We thank NASA, the Max Planck Society, and the German and Italian Space Agencies for support for this

investigation.

Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, Göttingen, 37077, Germany

T. Platz, A. Nathues, M. Schäfer, G. S. Thangjam, M. Hoffmann, P. Gutierrez-Marques, W. Dietrich & J. Ripken

University of Hawaii at Manoa, Institute for Astronomy, 2680 Woodlawn Drive, Honululu, 96822, Hawaii, USA

German Aerospace Center (DLR), Institute of Planetary Research, Rutherfordstrasse 2, Berlin, 12489, Germany

NASA Goddard Space Flight Center, Greenbelt, 20771, Maryland, USA

The University of Arizona, Lunar and Planetary Laboratory, 1629 East University Boulevard, Tucson, 85721, Arizona, USA

Freie Universität Berlin, Planetary Sciences and Remote Sensing, Malteserstrasse 74-100, Berlin, 12249, Germany

Bear Fight Institute, 22 Fiddler’s Road, PO Box 667, Winthrop, 98862, Washington, USA

University of California Los Angeles, Institute of Geophysics and Planetary Physics, Los Angeles, 90024, California, USA

T.P. designed the concept of this study, developed the threshold methodology, performed the image processing and prepared the manuscript. A.N., N.Scho., F.P., E.M., S.E.S., M.S., M.H.,

P.G.-M., W.D., J.R., K.-D.M. and C.T.R. contributed to the development of data analysis and interpretation. S.B. and M.E.L. performed the temperature calculations. Crater analysis and impact

simulation were performed by T.K. and N.Schm., respectively. J.-P.C. and G.S.T. analysed the VIR data. All authors discussed and contributed to the preparation of this manuscript.

Supplementary Figures 1–8 with captions, Supplementary Table 1 with caption, captions for Supplementary Videos 1 and 2. (PDF 2318 kb)

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