Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Differentiation of the asteroid Ceres as revealed by its shape


The accretion of bodies in the asteroid belt was halted nearly 4.6 billion years ago by the gravitational influence of the newly formed giant planet Jupiter. The asteroid belt therefore preserves a record of both this earliest epoch of Solar System formation and variation of conditions within the solar nebula. Spectral features in reflected sunlight indicate that some asteroids have experienced sufficient thermal evolution to differentiate into layered structures1. The second most massive asteroid—4 Vesta—has differentiated to a crust, mantle and core2,3. 1 Ceres, the largest and most massive asteroid, has in contrast been presumed to be homogeneous, in part because of its low density, low albedo and relatively featureless visible reflectance spectrum, similar to carbonaceous meteorites that have suffered minimal thermal processing4. Here we show that Ceres has a shape and smoothness indicative of a gravitationally relaxed object. Its shape is significantly less flattened than that expected for a homogeneous object, but is consistent with a central mass concentration indicative of differentiation. Possible interior configurations include water-ice-rich mantles over a rocky core.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Rotation of a bright spot on Ceres.
Figure 2: The shape of Ceres.
Figure 3: Interior models of Ceres.

Similar content being viewed by others


  1. McSween, H. Y., Ghosh, A., Grimm, E., Wilson, L. & Young, E. D. in Asteroids III (eds Bottke, W. et al.) 559–571 (Univ. Arizona Press, Tucson, 2002)

    Google Scholar 

  2. McCord, T. B., Adams, J. B. & Johnson, T. V. Asteroid Vesta: Spectral reflectivity and compositional implications. Science 168, 1445–1447 (1970)

    Article  ADS  CAS  Google Scholar 

  3. Ghosh, A. & McSween, H. Y. Jr A thermal model for the differentiation of asteroid 4 Vesta, based on radiogenic heating. Icarus 134, 187–206 (1998)

    Article  ADS  CAS  Google Scholar 

  4. McCord, T. B. & Sotin, C. Ceres: Evolution and current state. J. Geophys. Res. 110, E05009, doi:10.1029/2004JE002244 (2005)

    Article  ADS  Google Scholar 

  5. Parker, J. Wm. et al. Ceres: High-resolution imaging with HST and the determination of physical properties. Adv. Space Res. (in the press)

  6. Thomas, P. C. et al. The shape of Io from Galileo limb measurements. Icarus 135, 175–180 (1998)

    Article  ADS  Google Scholar 

  7. Johnson, T. V. & McGetchin, T. R. Topography on satellite surfaces and the shape of asteroids. Icarus 18, 612–620 (1973)

    Article  ADS  CAS  Google Scholar 

  8. Millis, R. L. et al. The size, shape, density, and albedo of Ceres from its occultation of BD + 8°471. Icarus 72, 507–518 (1987)

    Article  ADS  Google Scholar 

  9. Schenk, P. M. Crater formation and modification on the icy satellites of Uranus and Saturn—Depth/diameter and central peak occurrence. J. Geophys. Res. 94, 3813–3832 (1989)

    Article  ADS  Google Scholar 

  10. Thomas, P. C. et al. Impact excavation on asteroid 4 Vesta: Hubble Space Telescope results. Science 277, 1492–1495 (1997)

    Article  ADS  CAS  Google Scholar 

  11. Viateau, B. & Rapport, N. Mass and density of asteroids (4) Vesta and (11) Parthenope. Astron. Astrophys. 370, 602–609 (2001)

    Article  ADS  Google Scholar 

  12. Hestroffer, D. On equilibrium shapes among binary asteroids. Bull. Am. Astron. Soc. 36, 861 (2004)

    ADS  Google Scholar 

  13. Dermott, S. F. Shapes and gravitational moments of satellites and asteroids. Icarus 37, 575–586 (1979)

    Article  ADS  Google Scholar 

  14. Chandrasekhar, S. Ellipsoidal Figures of Equilibrium (Yale Univ. Press, New Haven, 1969)

    MATH  Google Scholar 

  15. Michalak, G. Determination of asteroid masses—I. (1) Ceres, (2) Pallas and (4) Vesta. Astron. Astrophys. 360, 363–374 (2000)

    ADS  Google Scholar 

  16. Britt, D. T. & Consolmagno, G. J. Stony meteorite porosities and densities: A review of the data through 2001. Meteorit. Planet. Sci. 38, 1161–1180 (2003)

    Article  ADS  CAS  Google Scholar 

  17. Veverka, J. et al. NEAR's flyby of 253 Mathilde: Images of a C asteroid. Science 278, 2109–2112 (1997)

    Article  ADS  CAS  Google Scholar 

  18. Thomas, P. C. Gravity, tides, and topography on small satellites and asteroids—Application to surface features of the Martian satellites. Icarus 105, 326–344 (1993)

    Article  ADS  Google Scholar 

  19. Melosh, H. J. Impact Cratering: A Geologic Process (Oxford Univ. Press, New York, 1989)

    Google Scholar 

  20. Farinella, P., Davis, D. R., Paolicchi, P., Cellino, A. & Zappala, Z. Asteroid collisional evolution: An integrated model for the evolution of asteroid rotation rates. Astron. Astrophys. 253, 604–614 (1992)

    ADS  Google Scholar 

  21. Wilson, L., Keil, K., Browning, L. B., Krot, A. N. & Bourcher, W. Early aqueous alteration, explosive disruption, and re-processing of asteroids. Meteorit. Planet. Sci 34, 541–557 (1999)

    Article  ADS  CAS  Google Scholar 

  22. Grimm, R. E. & McSween, H. Y. Water and the thermal evolution of carbonaceous chondrite parent bodies. Icarus 82, 244–280 (1989)

    Article  ADS  Google Scholar 

  23. Lebofsky, L. A. et al. The 1.7- to 4.2-micron spectrum of asteroid 1 Ceres—Evidence for structural water in clay minerals. Icarus 48, 453–459 (1981)

    Article  ADS  CAS  Google Scholar 

  24. Feierberg, M. A., Lebofsky, L. A. & Larson, H. P. Spectroscopic evidence for aqueous alteration products on the surfaces of low-albedo asteroids. Geochim. Cosmochim. Acta 45, 971–981 (1981)

    Article  ADS  CAS  Google Scholar 

  25. King, T. V. et al. Evidence for ammonium-bearing minerals on Ceres. Science 255, 1551–1553 (1992)

    Article  ADS  CAS  Google Scholar 

  26. Rivkin, A. S. Observations of Main-belt Asteroids in the 3-µm Region. Ph.D. dissertation, Univ. Arizona (1997)

    Google Scholar 

  27. Fanale, F. P. & Salvail, J. R. The water regime of asteroid 1 Ceres. Icarus 82, 97–110 (1989)

    Article  ADS  CAS  Google Scholar 

  28. Saint-Pe, O., Combes, M. & Rigaut, F. Ceres surface properties by high-resolution imaging from earth. Icarus 105, 263–271 (1993)

    Article  ADS  Google Scholar 

  29. Drummond, J. O., Fungate, R. Q. & Christou, J. G. Full adaptive optics images of asteroids Ceres and Vesta; rotational poles and triaxial ellipsoid dimensions. Icarus 132, 80–99 (1998)

    Article  ADS  Google Scholar 

  30. Pavlovsky, C. et al. ACS Instrument Handbook, Version 5.0 (Space Telescope Science Institute, Baltimore, 2004)

    Google Scholar 

Download references


We thank B. Carcich and K. Consroe for technical assistance. J. Burns and J. Veverka provided discussions. This work was supported by NASA through the Space Telescope Science Institute, which is operated by the Association of Universities for Research and Astronomy, Inc. L.A.M., C.T.R. and M.V.S. were supported by NASA's Dawn Discovery mission. A review by S. Dermott improved the manuscript.

Author information

Authors and Affiliations


Corresponding author

Correspondence to P. C. Thomas.

Ethics declarations

Competing interests

Reprints and permissions information is available at The authors declare no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Thomas, P., Parker, J., McFadden, L. et al. Differentiation of the asteroid Ceres as revealed by its shape. Nature 437, 224–226 (2005).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing