Letter | Published:

Cohesive forces prevent the rotational breakup of rubble-pile asteroid (29075) 1950 DA

Nature volume 512, pages 174176 (14 August 2014) | Download Citation

Abstract

Space missions1 and ground-based observations2 have shown that some asteroids are loose collections of rubble rather than solid bodies. The physical behaviour of such ‘rubble-pile’ asteroids has been traditionally described using only gravitational and frictional forces within a granular material3. Cohesive forces in the form of small van der Waals forces between constituent grains have recently been predicted to be important for small rubble piles (ten kilometres across or less), and could potentially explain fast rotation rates in the small-asteroid population4,5,6. The strongest evidence so far has come from an analysis of the rotational breakup of the main-belt comet P/2013 R3 (ref. 7), although that was indirect and poorly constrained by observations. Here we report that the kilometre-sized asteroid (29075) 1950 DA (ref. 8) is a rubble pile that is rotating faster than is allowed by gravity and friction. We find that cohesive forces are required to prevent surface mass shedding and structural failure, and that the strengths of the forces are comparable to, though somewhat less than, the forces found between the grains of lunar regolith.

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References

  1. 1.

    et al. The rubble-pile asteroid Itokawa as observed by Hayabusa. Science 312, 1330–1334 (2006)

  2. 2.

    et al. Orbit and bulk density of the OSIRIS-REx target asteroid (101955) Bennu. Icarus 235, 5–22 (2014)

  3. 3.

    , & Spin-up of rubble-pile asteroids: disruption, satellite formation, and equilibrium shapes. Icarus 220, 514–529 (2012)

  4. 4.

    Spin limits of Solar System bodies: from the small fast-rotators to 2003 EL61. Icarus 187, 500–509 (2007)

  5. 5.

    , , & Scaling forces to asteroid surfaces: the role of cohesion. Icarus 210, 968–984 (2010)

  6. 6.

    & The strength of regolith and rubble pile asteroids. Meteorit. Planet. Sci. 49, 788–811 (2014)

  7. 7.

    , , & Constraints on the physical properties of main belt comet P/2013 R3 from its breakup event. Astrophys. J. 789, L12 (2014)

  8. 8.

    et al. Physical modeling of near-Earth asteroid (29075) 1950 DA. Icarus 190, 608–621 (2007)

  9. 9.

    & Fast and slow rotation of asteroids. Icarus 148, 12–20 (2000)

  10. 10.

    , , & The Yarkovsky and YORP effects: implications for asteroid dynamics. Annu. Rev. Earth Planet. Sci. 34, 157–191 (2006)

  11. 11.

    et al. Thermal infrared observations and thermophysical characterization of OSIRIS-REx target asteroid (101955) Bennu. Icarus 234, 17–35 (2014)

  12. 12.

    & Assessment of the 2880 impact threat from asteroid (29075) 1950 DA. Icarus 229, 321–327 (2014)

  13. 13.

    & Directional characteristics of thermal-infrared beaming from atmosphereless planetary surfaces—a new thermophysical model. Mon. Not. R. Astron. Soc. 415, 2042–2062 (2011)

  14. 14.

    & The influence of rough surface thermal-infrared beaming on the Yarkovsky and YORP effects. Mon. Not. R. Astron. Soc. 423, 367–388 (2012)

  15. 15.

    et al. NEOWISE observations of near-Earth objects: preliminary results. Astrophys. J. 743, 156 (2011)

  16. 16.

    , & Constraining near-Earth object albedos using near-infrared spectroscopy. Icarus 175, 175–180 (2005)

  17. 17.

    et al. Images of asteroid 21 Lutetia: a remnant planetesimal from the early Solar System. Science 334, 487–490 (2011)

  18. 18.

    Heat conductivity and nature of the lunar surface material. Bull. Astron. Inst. Netherlands 10, 351–360 (1948)

  19. 19.

    , , & Apollo soil mechanics experiment S-200 final report. Space Sciences Laboratory Series 15, 72–85 (Univ. California, Berkeley, 1974);

  20. 20.

    et al. Size-frequency statistics of boulders on global surface of asteroid 25143 Itokawa. Earth Planets Space 60, 13–20 (2008)

  21. 21.

    , , , & Thermal infrared observations of the Hayabusa spacecraft target asteroid 25143 Itokawa. Astron. Astrophys. 443, 347–355 (2005)

  22. 22.

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

  23. 23.

    et al. The impact and recovery of asteroid 2008 TC3. Nature 458, 485–488 (2009)

  24. 24.

    & Deflection and fragmentation of near-Earth asteroids. Nature 360, 429–433 (1992)

  25. 25.

    et al. Simulating regoliths in microgravity. Mon. Not. R. Astron. Soc. 433, 506–514 (2013)

  26. 26.

    , , & A thermophysical analysis of the (1862) Apollo Yarkovsky and YORP effects. Astron. Astrophys. 555, A20 (2013)

  27. 27.

    et al. The Wide-field Infrared Survey Explorer (WISE): mission description and initial on-orbit performance. Astron. J. 140, 1868–1881 (2010)

  28. 28.

    Solar Radiation and near-Earth asteroids: Thermophysical Modeling and New Measurements of the Yarkovsky Effect. 3556842, , PhD thesis, Univ. California, Los Angeles (ProQuest, UMI Dissertations Publishing, 2013)

  29. 29.

    et al. Near Earth asteroids with measurable Yarkovsky effect. Icarus 224, 1–13 (2013)

  30. 30.

    & Exterior gravitation of a polyhedron derived and compared with harmonic and mascon gravitation representations of asteroid 4769 Castalia. Celestial Mech. Dyn. Astron. 65, 313–344 (1997)

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Acknowledgements

This publication uses data products from NEOWISE, a project of the Jet Propulsion Laboratory/California Institute of Technology, funded by the Planetary Science Division of NASA. We made use of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory/California Institute of Technology under a contract with NASA. This work was supported by NASA contract NNM10AA11C (Principal Investigator D. S. Lauretta) through the New Frontiers programme, and by NASA contract NNX12AP32G (Principal Investigator J. P. Emery) through the Near-Earth Object Observing programme.

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Affiliations

  1. Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee 37996, USA

    • Ben Rozitis
    • , Eric MacLennan
    •  & Joshua P. Emery

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Contributions

B.R. performed the thermophysical and cohesive force analyses, E.M. retrieved the WISE data and helped with its analysis, and J.P.E. helped with the scientific interpretation of the results. B.R. wrote the manuscript with all co-authors contributing to its final form.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Ben Rozitis.

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https://doi.org/10.1038/nature13632

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