The typically dark surface of the dwarf planet Ceres is punctuated by areas of much higher albedo, most prominently in the Occator crater1. These small bright areas have been tentatively interpreted as containing a large amount of hydrated magnesium sulfate1, in contrast to the average surface, which is a mixture of low-albedo materials and magnesium phyllosilicates, ammoniated phyllosilicates and carbonates2,3,4. Here we report high spatial and spectral resolution near-infrared observations of the bright areas in the Occator crater on Ceres. Spectra of these bright areas are consistent with a large amount of sodium carbonate, constituting the most concentrated known extraterrestrial occurrence of carbonate on kilometre-wide scales in the Solar System. The carbonates are mixed with a dark component and small amounts of phyllosilicates, as well as ammonium carbonate or ammonium chloride. Some of these compounds have also been detected in the plume of Saturn’s sixth-largest moon Enceladus5. The compounds are endogenous and we propose that they are the solid residue of crystallization of brines and entrained altered solids that reached the surface from below. The heat source may have been transient (triggered by impact heating). Alternatively, internal temperatures may be above the eutectic temperature of subsurface brines, in which case fluids may exist at depth on Ceres today.

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We thank the following institutions and agencies which supported this work: the Italian Space Agency, the National Aeronautics and Space Administration (NASA, USA) and the Deutsches Zentrum für Luft- und Raumfahrt (DLR, Germany). The VIR was funded and coordinated by the Italian Space Agency and built by SELEX ES, with the scientific leadership of the Institute for Space Astrophysics and Planetology and the Italian National Institute for Astrophysics, and is operated by the Institute for Space Astrophysics and Planetology, Italy. A portion of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, USA, under contract to NASA. We also thank the Dawn Mission Operations team and the Framing Camera team.

Author information


  1. Istituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica (INAF), Via del Fosso del Cavaliere 100, 00133 Rome, Italy

    • M. C. De Sanctis
    • , A. Raponi
    • , E. Ammannito
    • , M. Ciarniello
    • , F. G. Carrozzo
    • , S. Marchi
    • , F. Tosi
    • , F. Zambon
    • , F. Capaccioni
    • , M. T. Capria
    • , S. Fonte
    • , M. Formisano
    • , A. Frigeri
    • , M. Giardino
    • , A. Longobardo
    • , G. Magni
    •  & E. Palomba
  2. Earth Planetary and Space Sciences, University of California, Los Angeles, California, USA

    • E. Ammannito
    •  & C. T. Russell
  3. Institut de Recherche d’Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS), Toulouse, France

    • M. J. Toplis
  4. Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee 37996-1410, USA

    • H. Y. McSween
  5. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA

    • J. C. Castillo-Rogez
    • , B. L. Ehlmann
    •  & C. A. Raymond
  6. Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA

    • B. L. Ehlmann
  7. Solar System Exploration Research Virtual Institute, Southwest Research Institute (SRI), 1050 Walnut Street, Boulder, Colorado 80302, USA

    • S. Marchi
  8. NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA

    • L. A. McFadden
  9. Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, Rhode Island 02912, USA

    • C. M. Pieters
  10. Institute of Planetary Research, German Aerospace Center (DLR), Rutherfordstrasse 2, 12489 Berlin, Germany

    • R. Jaumann
  11. Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, Texas 77058, USA

    • P. Schenk
  12. Agenzia Spaziale Italiana, Via del Politecnico, 00133 Roma, Rome, Italy

    • R. Mugnuolo


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M.C.D.S., A.R., E.A. and F.G.C. performed data analysis and calibration. M.C. provided optical constants from reflectance spectra. M.C.D.S., C.M.P. and B.L.E. contributed to the spectral interpretation of the data. All authors contributed to the discussion of the results and to writing the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to M. C. De Sanctis.

The VIR calibrated data will be made available through the PDS Small Bodies Node website (http://sbn.pds.nasa.gov/).

Reviewer Information Nature thanks V. Reddy, A. S. Rivkin and M. M. Zolotov for their contribution to the peer review of this work.

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