True polar wander of Ceres due to heterogeneous crustal density

Abstract

Ceres is the largest body in the main asteroid belt. It was recently explored by the Dawn mission to uncover strong similarities with other icy bodies. The morphological features observed on the surface of Ceres indicate a relatively wide range of water ice concentrations, leading us to investigate the magnitude and distribution of crustal density heterogeneities, and to consider whether they could have caused a reorientation of Ceres. Here, we present three independent and corroborating lines of evidence for the true polar wander of Ceres. Thanks to the global gravity inversion approach applied to the shape and gravity data of Ceres, we find crustal density heterogeneities up to approximately ±0.3 g cm3, with a prominent positive density anomaly aligned with the equator, in the region of Ahuna Mons. The topography shows the remnants of an equatorial ridge compatible with the position of the palaeo-equator, and indicates that Ceres reoriented by approximately 36°, with the palaeo-pole following an indirect path to the current pole of Ceres. The tectonic patterns generated by the true polar wander are in close agreement with the location and orientation of the Samhain Catenae and Uhola Catenae crustal fractures. These results highlight the complex interior structure and richness of processes taking place in Ceres-scale icy bodies.

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Fig. 1: Range of interior structure solutions.
Fig. 2: Topography and surface density of Ceres.
Fig. 3: Palaeo-pole of Ceres.
Fig. 4: Expected tectonic pattern of Ceres due to reorientation.

Data availability

The Ceres shape and gravity data from the Dawn mission are available through the NASA Planetary Data System Small Bodies Node (https://sbn.psi.edu/pds/resource/dawn/). The data that support the findings of this study are available on request from the author.

References

  1. 1.

    Lebofsky, L. A., Feierberg, M. A., Tokunaga, A. T., Larson, H. P. & Johnson, J. R. The 1.7- to 4.2-micron spectrum of asteroid 1 Ceres—evidence for structural water in clay minerals. Icarus 48, 453–459 (1981).

    Google Scholar 

  2. 2.

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

    Google Scholar 

  3. 3.

    Milliken, R. E. & Rivkin, A. S. Brucite and carbonate assemblages from altered olivine-rich materials on Ceres. Nat. Geosci. 2, 258–261 (2009).

    Google Scholar 

  4. 4.

    Russell, C. T. et al. Dawn arrives at Ceres: exploration of a small, volatile-rich world. Science 353, 1008–1010 (2016).

    Google Scholar 

  5. 5.

    Prettyman, T. H. et al. Extensive water ice within Ceres’ aqueously altered regolith: evidence from nuclear spectroscopy. Science 355, 55–59 (2017).

    Google Scholar 

  6. 6.

    Nathues, A. et al. Sublimation in bright spots on (1) Ceres. Nature 528, 237–240 (2015).

    Google Scholar 

  7. 7.

    Bland, M. T. et al. Composition and structure of the shallow subsurface of Ceres revealed by crater morphology. Nat. Geosci. 9, 538–542 (2016).

    Google Scholar 

  8. 8.

    Hiesinger, H. et al. Cratering on Ceres: implications for its crust and evolution. Science 353, aaf4758 (2016).

    Google Scholar 

  9. 9.

    Schmidt, B. E. et al. Geomorphological evidence for ground ice on dwarf planet Ceres. Nat. Geosci. 10, 338–343 (2017).

    Google Scholar 

  10. 10.

    Park, R. S. et al. A partially differentiated interior for (1) Ceres deduced from its gravity field and shape. Nature 537, 515–517 (2016).

    Google Scholar 

  11. 11.

    Konopliv, A. S. et al. The Ceres gravity field, spin pole, rotation period and orbit from the Dawn radiometric tracking and optical data. Icarus 299, 411–429 (2018).

    Google Scholar 

  12. 12.

    Ermakov, A. I. et al. Constraints on Ceres’ internal structure and evolution from its shape and gravity measured by the dawn spacecraft. J. Geophys. Res. Planets 122, 2267–2293 (2017).

    Google Scholar 

  13. 13.

    Mao, X. & McKinnon, W. B. Faster paleospin and deep-seated uncompensated mass as possible explanations for Ceres’ present-day shape and gravity. Icarus 299, 430–442 (2018).

    Google Scholar 

  14. 14.

    Fu, R. R. et al. The interior structure of Ceres as revealed by surface topography. Earth Planet. Sci. Lett. 476, 153–164 (2017).

    Google Scholar 

  15. 15.

    Tricarico, P. Multi-layer hydrostatic equilibrium of planets and synchronous moons: theory and application to Ceres and to Solar System moons. Astrophys. J. 782, 99 (2014).

    Google Scholar 

  16. 16.

    Rambaux, N., Chambat, F. & Castillo-Rogez, J. C. Third-order development of shape, gravity, and moment of inertia for highly flattened celestial bodies. Application to Ceres. Astron. Astrophys. 584, A127 (2015).

    Google Scholar 

  17. 17.

    Tricarico, P. Global gravity inversion of bodies with arbitrary shape. Geophys. J. Int. 195, 260–275 (2013).

    Google Scholar 

  18. 18.

    Stacey, F. D. & Davis, P. M. Physics of the Earth (Cambridge Univ. Press, Cambridge, 2008).

  19. 19.

    Ruesch, O. et al. Cryovolcanism on Ceres. Science 353, aaf4286 (2016).

    Google Scholar 

  20. 20.

    Watters, W. A., Zuber, M. T. & Hager, B. H. Thermal perturbations caused by large impacts and consequences for mantle convection. J. Geophys. Res. Planets 114, E02001 (2009).

    Google Scholar 

  21. 21.

    Zuber, M. T. The crust and mantle of Mars. Nature 412, 220–227 (2001).

    Google Scholar 

  22. 22.

    Reese, C. C., Solomatov, V. S., Baumgardner, J. R., Stegman, D. R. & Vezolainen, A. V. Magmatic evolution of impact-induced Martian mantle plumes and the origin of Tharsis. J. Geophys. Res. Planets 109, E08009 (2004).

    Google Scholar 

  23. 23.

    Zuber, M. T. & Smith, D. E. Mars without Tharsis. J. Geophys. Res. 102, 28673–28686 (1997).

    Google Scholar 

  24. 24.

    Marchi, S. et al. The missing large impact craters on Ceres. Nat. Commun. 7, 12257 (2016).

    Google Scholar 

  25. 25.

    Travis, B. J. & Schubert, G. Hydrothermal convection in carbonaceous chondrite parent bodies [rapid communication]. Earth Planet. Sci. Lett. 240, 234–250 (2005).

    Google Scholar 

  26. 26.

    Bland, P. A. & Travis, B. J. Giant convecting mud balls of the early Solar System. Sci. Adv. 3, e1602514 (2017).

    Google Scholar 

  27. 27.

    Travis, B. J., Bland, P. A., Feldman, W. C. & Sykes, M. V. Hydrothermal dynamics in a cm-based model of Ceres. 53, 2008–2032 (2018).

  28. 28.

    Melosh, H. J. Global tectonics of a despun planet. Icarus 31, 221–243 (1977).

    Google Scholar 

  29. 29.

    Matsuyama, I. & Nimmo, F. Tectonic patterns on reoriented and despun planetary bodies. Icarus 195, 459–473 (2008).

    Google Scholar 

  30. 30.

    McCord, T. B. & Sotin, C. Ceres: evolution and current state. J. Geophys. Res. Planets 110, E05009 (2005).

    Google Scholar 

  31. 31.

    Castillo-Rogez, J. C. & McCord, T. B. Ceres’ evolution and present state constrained by shape data. Icarus 205, 443–459 (2010).

    Google Scholar 

  32. 32.

    Porco, C. C. et al. Cassini imaging science: initial results on Phoebe and Iapetus. Science 307, 1237–1242 (2005).

    Google Scholar 

  33. 33.

    Castillo-Rogez, J. C. et al. Iapetus’ geophysics: rotation rate, shape, and equatorial ridge. Icarus 190, 179–202 (2007).

    Google Scholar 

  34. 34.

    Durham, W. B., Kirby, S. H., Stern, L. A. & Ragaini, K. A. Brittle and ductile behavior of ice/rock mixtures. Proc. Lunar Planet. Sci. Conf. 20, 254 (1989).

    Google Scholar 

  35. 35.

    Matsuyama, I. & Nimmo, F. Reorientation of Vesta: gravity and tectonic predictions. Geophys. Res. Lett. 38, L14205 (2011).

    Google Scholar 

  36. 36.

    Buczkowski, D. L. et al. The geomorphology of Ceres. Science 353, aaf4332 (2016).

    Google Scholar 

  37. 37.

    Scully, J. E. C. et al. Evidence for the interior evolution of Ceres from geologic analysis of fractures. Geophys. Res. Lett. 44, 9564–9572 (2017).

    Google Scholar 

  38. 38.

    Schenk, P., Matsuyama, I. & Nimmo, F. True polar wander on Europa from global-scale small-circle depressions. Nature 453, 368–371 (2008).

    Google Scholar 

  39. 39.

    Crown, D. et al. Geologic mapping of the Urvara and Yalode quadrangles of Ceres. https://doi.org/10.1016/j.icarus.2017.08.004 (2017).

  40. 40.

    Sori, M. M. et al. The vanishing cryovolcanoes of Ceres. Geophys. Res. Lett. 44, 1243–1250 (2017).

    Google Scholar 

  41. 41.

    Buczkowski, D. L. et al. Tectonic analysis of fracturing associated with Occator crater. https://doi.org/10.1016/j.icarus.2018.05.012 (2018).

  42. 42.

    De Sanctis, M. C. et al. Ammoniated phyllosilicates with a likely outer Solar System origin on (1) Ceres. Nature 528, 241–244 (2015).

    Google Scholar 

  43. 43.

    Wessel, P. & Smith, W. H. F. Free software helps map and display data. EOS Trans. 72, 441–446 (1991).

    Google Scholar 

  44. 44.

    Kaula, W. M. Theory of Satellite Geodesy. Applications of Satellites to Geodesy (Dover, Mineola, 1966).

  45. 45.

    Yoder, C. F. in Global Earth Physics: A Handbook of Physical Constants (ed. Ahrens, T. J.) 1–31 (AGU, Washington DC, 1995).

  46. 46.

    Tricarico, P. Figure–figure interaction between bodies having arbitrary shapes and mass distributions: a power series expansion approach. Celest. Mech. Dyn. Astron. 100, 319–330 (2008).

    Google Scholar 

  47. 47.

    Golub, G. H. & Van Loan, C. F. Matrix Computations (John Hopkins Univ. Press, Baltimore, 1996).

  48. 48.

    Kirkpatrick, S., Gelatt, C. D. & Vecchi, M. P. Optimization by simulated annealing. Science 220, 671–680 (1983).

    Google Scholar 

  49. 49.

    Barnes, J. E. Gravitational softening as a smoothing operation. Mon. Not. R. Astron. Soc. 425, 1104–1120 (2012).

    Google Scholar 

  50. 50.

    Waldvogel, J. The Newtonian potential of homogeneous polyhedra. Z. Angew. Math. Phys. 30, 388–398 (1979).

    Google Scholar 

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Acknowledgements

I am grateful to the Dawn team for the Ceres data, and to M. Sykes for the long-time encouragement and support. I thank G. Mitri for insightful discussions. This research is supported by NASA grants NNX16AB60G and NNX10AR20G.

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P.T. carried out the work described in this manuscript.

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Correspondence to P. Tricarico.

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Tricarico, P. True polar wander of Ceres due to heterogeneous crustal density. Nature Geosci 11, 819–824 (2018). https://doi.org/10.1038/s41561-018-0232-3

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