Skip to main content

Thank you for visiting nature.com. 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.

Craters, boulders and regolith of (101955) Bennu indicative of an old and dynamic surface

A Publisher Correction to this article was published on 04 April 2019

This article has been updated

Abstract

Small, kilometre-sized near-Earth asteroids are expected to have young and frequently refreshed surfaces for two reasons: collisional disruptions are frequent in the main asteroid belt where they originate, and thermal or tidal processes act on them once they become near-Earth asteroids. Here we present early measurements of numerous large candidate impact craters on near-Earth asteroid (101955) Bennu by the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) mission, which indicate a surface that is between 100 million and 1 billion years old, predating Bennu’s expected duration as a near-Earth asteroid. We also observe many fractured boulders, the morphology of which suggests an influence of impact or thermal processes over a considerable amount of time since the boulders were exposed at the surface. However, the surface also shows signs of more recent mass movement: clusters of boulders at topographic lows, a deficiency of small craters and infill of large craters. The oldest features likely record events from Bennu’s time in the main asteroid belt.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: The boulders of Bennu can be large and are sometimes fractured or brecciated.
Fig. 2: Boulder abundance map of the surface of Bennu.
Fig. 3: Examples of Bennu’s craters.
Fig. 4: Flow of material into a D = 160 m candidate crater.

Data availability

Raw through to calibrated datasets will be available via the Planetary Data System (PDS) (https://sbn.psi.edu/pds/resource/orex/). Data are delivered to the PDS according to the OSIRIS-REx Data Management Plan available in the OSIRIS-REx PDS archive. Higher-level products, for example, global mosaics and elevation maps, will be available in the PDS one year after departure from the asteroid.

Change history

  • 04 April 2019

    An amendment to this paper has been published and can be accessed via a link at the top of the paper.

References

  1. 1.

    Lauretta, D. S. et al. The unexpected surface of asteroid (101955) Bennu. Nature https://doi.org/10.1038/s41586-019-1033-6 (2019).

  2. 2.

    DellaGiustina, D. N. et al. Properties of rubble-pile asteroid (101955) Bennu from OSIRIS-REx imaging and thermal analysis. Nat. Astron. https://doi.org/10.1038/s41550-019-0731-1 (2019).

  3. 3.

    Rizk, B. et al. OCAMS: the OSIRIS-REx camera suite. Space Sci. Rev. 214, 26 (2018).

    Article  Google Scholar 

  4. 4.

    Barnouin, O. S. et al. Shape of (101955) Bennu indicative of a rubble pile with internal stiffness. Nat. Geosci. https://doi.org/10.1038/s41561-019-0330-x (2019).

  5. 5.

    Nolan, M. C. et al. Shape model and surface properties of the OSIRIS-REx target asteroid (101955) Bennu from radar and lightcurve observations. Icarus 226, 629–640 (2013).

    Article  Google Scholar 

  6. 6.

    Richardson, D. C., Leinhardt, Z. M., Melosh, H. J., Bottke, W. F. & Asphaug, E. in Asteroids III (eds Bottke, W. F. Jr, Cellino, A., Paolicchi, P. & Binzel, R. P.) 501–515 (Univ. Arizona Press, 2002).

  7. 7.

    Walsh, K. J. Rubble pile asteroids. Annu. Rev. Astron. Astrophys. 56, 593–624 (2018).

    Article  Google Scholar 

  8. 8.

    Michel, P., Benz, W., Tanga, P. & Richardson, D. C. Collisions and gravitational reaccumulation: forming asteroid families and satellites. Science 294, 1696–1700 (2001).

    Article  Google Scholar 

  9. 9.

    Bottke, W. F. et al. Dynamical spreading of asteroid families by the Yarkovsky effect. Science 294, 1693–1696 (2001).

    Article  Google Scholar 

  10. 10.

    Fujiwara, A. et al. The rubble-pile asteroid Itokawa as observed by Hayabusa. Science 312, 1330 (2006).

    Article  Google Scholar 

  11. 11.

    Miyamoto, H. et al. Regolith migration and sorting on asteroid Itokawa. Science 316, 1011–1014 (2007).

    Article  Google Scholar 

  12. 12.

    Hirata, N. et al. A survey of possible impact structures on 25143 Itokawa. Icarus 200, 486 (2009).

    Article  Google Scholar 

  13. 13.

    Scheeres, D. N. et al. The dynamic geophysical environment of (101955) Bennu based on OSIRIS-REx measurements. Nat. Astron. https://doi.org/10.1038/s41550-019-0721-3 (2019).

  14. 14.

    Hamilton, V. E. et al. Evidence for widespread hydrated minerals on asteroid (101955) Bennu. Nat. Astron. https://doi.org/10.1038/s41550-019-0722-2 (2019).

  15. 15.

    Macke, R. J., Consolmagno, G. J. & Britt, D. T. Density, porosity, and magnetic susceptibility of carbonaceous chondrites. Meteorit. Planet. Sci. 46, 1842–1862 (2011).

    Article  Google Scholar 

  16. 16.

    Ostro, S. J. et al. Radar imaging of binary near-Earth asteroid (66391) 1999 KW4. Nature 314, 1276–1280 (2006).

    Google Scholar 

  17. 17.

    Bart, G. D. & Melosh, H. J. Using lunar boulders to distinguish primary from distant secondary impact craters. Geophys. Res. Lett. 34, L07203 (2007).

    Google Scholar 

  18. 18.

    Bischoff, A., Edward, R. D. S., Metzler, K. & Goodrich, C. A. in Meteorites and the Early Solar System II (eds Lauretta, D. S. & McSween H. Y. Jr) 679–712 (Univ. Arizona Press, 2006).

  19. 19.

    Noguchi, T. et al. Surface morphological features of boulders on Asteroid 25143 Itokawa. Icarus 206, 319–326 (2010).

    Article  Google Scholar 

  20. 20.

    Molaro, J. L., Byrne, S. & Le, J. L. Thermally induced stresses in boulders on airless body surfaces, and implications for rock breakdown. Icarus 294, 247–261 (2017).

    Article  Google Scholar 

  21. 21.

    Delbo’, M. et al. Thermal fatigue as the origin of regolith on small asteroids. Nature 508, 233–236 (2014).

    Article  Google Scholar 

  22. 22.

    Basilevsky, A. T., Head, J. W., Horz, F. & Ramsley, K. Survival times of meter-sized rock boulders on the surface of airless bodies. Planet. Space Sci. 117, 312–328 (2015).

    Article  Google Scholar 

  23. 23.

    Gladman, B., Michel, P. & Froeschlé, C. The near-Earth object population. Icarus 146, 176–189 (2000).

    Article  Google Scholar 

  24. 24.

    Graves, K. J., Minton, D. A., Molaro, J. L. & Hirabayashi, M. Resurfacing asteroids from thermally induced surface degradation. Icarus 322, 1–’12 (2019).

    Article  Google Scholar 

  25. 25.

    Bottke, W. F. et al. The fossilized size distribution of the main asteroid belt. Icarus 175, 111–140 (2005).

    Article  Google Scholar 

  26. 26.

    Holsapple, K. A. The scaling of impact processes in planetary sciences. Ann. Rev. Earth Planet. Sci. 21, 333–373 (1993).

    Article  Google Scholar 

  27. 27.

    Holsapple, K. A. & Housen, K. R. A crater and its ejecta: an interpretation of Deep Impact. Icarus 187, 345–356 (2007).

    Article  Google Scholar 

  28. 28.

    Bottke, W. F., Nolan, M. C., Greenberg, R. & Kolvoord, R. A. Velocity distributions among colliding asteroids. Icarus 107, 255–268 (1994).

    Article  Google Scholar 

  29. 29.

    Prieur, N. C. et al. The effect of target properties on transient crater scaling for simple craters. J. Geophys. Res. Planets 122, 1704–1726 (2017).

    Article  Google Scholar 

  30. 30.

    Thomas, P. C. & Robinson, M. S. Seismic resurfacing by a single impact on the asteroid 433 Eros. Nature 436, 366–369 (2005).

    Article  Google Scholar 

  31. 31.

    Michel, P., O’Brien, D. P., Abe, S. & Hirata, N. Itokawa’s cratering record as observed by Hayabusa: implications for its age and collisional history. Icarus 200, 503–513 (2009).

    Article  Google Scholar 

  32. 32.

    Tatsumi, E. & Sugita, S. Cratering efficiency on coarse-grain targets: Implications for the dynamical evolution of asteroid 25143 Itokawa. Icarus 300, 227–248 (2017).

    Article  Google Scholar 

  33. 33.

    Richardson, J. E., Melosh, H. J., Greenberg, R. J. & O’Brien, D. P. The global effects of impact-induced seismic activity on fractured asteroid surface morphology. Icarus 179, 325–349 (2005).

    Article  Google Scholar 

  34. 34.

    Asphaug, E. Critical crater diameter and asteroid impact seismology. Meteorit. Planet. Sci. 43, 1075–1084 (2008).

    Article  Google Scholar 

  35. 35.

    Bierhaus, E. B. et al. The OSIRIS-REx spacecraft and the touch-and-go sample acquisition mechanism (TAGSAM). Space Sci. Rev. 214, 107 (2018).

    Article  Google Scholar 

  36. 36.

    Michel, P. et al. Disruption and reaccumulation as the possible origins of Ryugu and Bennu top shapes. In Lunar Planetary Sci. Conf. 50 abstr. 1659 (2019).

  37. 37.

    Lauretta, D. S. et al. OSIRIS-REx: sample return from asteroid (101955) Bennu. Space Sci. Rev. 212, 925–984 (2017).

    Article  Google Scholar 

  38. 38.

    Ernst, C. M., Barnouin, O. S. & Daly, R. T. The Small Body Mapping Tool (SBMT) for accessing, visualizing, and analyzing spacecraft data in three dimensions. In Lunar Planetary Sci. Conf. 49 abstr. 1043 (2018).

  39. 39.

    Marchi et al. The cratering history of (2867) Steins. Planet. Space Sci. 58, 1116–1123 (2010).

    Article  Google Scholar 

Download references

Acknowledgements

This material is based on work supported by NASA under contracts NNM10AA11C and NNH09ZDA007O issued through the New Frontiers Program. M.P. was supported for this research by the Italian Space Agency (ASI) under the ASI-INAF agreement no. 2017–37-H.0. M.D., P.M., and A.R. would like to acknowledge the French space agency CNES. M.D., A.R., P.M. and S.R.S acknowledge support from the Academies of Excellence on Complex Systems and Space, Environment, Risk and Resilience of the Initiative d’EXcellence ‘Joint, Excellent, and Dynamic Initiative’ (IDEX JEDI) of the Université Côte d’Azur. Part of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Author information

Affiliations

Authors

Consortia

Contributions

K.J.W. led the mapping, analysis and manuscript writing. E.R.J., R.-L.B., O.S.B., E.B.B., H.C.C., J.L.M. and T.J.M. contributed to the mapping, analysis and writing of the manuscript. D.S.L. leads the mission and contributed to analysis and writing. M.D., C.M.H., M.P., S.R.S. and D.T. contributed to mapping and manuscript writing. E.A., K.J.B., C.B.B., W.F.B., C.A.B., K.N.B., B.C.C., M.G.D., D.N.D., J.P.D., C.M.E., D.R.G., A.R.H., R.M., J.M., P.M., M.C.N., M.E.P., B.R., A.R., D.J.S., H.C.C., S.A.S., H.C.M.S. and F.T. all contributed to the mapping, analysis or manuscript writing. The entire OSIRIS-REx Team made the Bennu encounter possible.

Corresponding author

Correspondence to K. J. Walsh.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Walsh, K.J., Jawin, E.R., Ballouz, RL. et al. Craters, boulders and regolith of (101955) Bennu indicative of an old and dynamic surface. Nat. Geosci. 12, 242–246 (2019). https://doi.org/10.1038/s41561-019-0326-6

Download citation

Further reading

Search

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