Letter | Published:

The recent breakup of an asteroid in the main-belt region

Naturevolume 417pages720721 (2002) | Download Citation



The present population of asteroids in the main belt is largely the result of many past collisions1,2. Ideally, the asteroid fragments resulting from each impact event could help us understand the large-scale collisions that shaped the planets during early epochs3,4,5. Most known asteroid fragment families, however, are very old and have therefore undergone significant collisional and dynamical evolution since their formation6. This evolution has masked the properties of the original collisions. Here we report the discovery of a family of asteroids that formed in a disruption event only 5.8 ± 0.2 million years ago, and which has subsequently undergone little dynamical and collisional evolution5,6. We identified 39 fragments, two of which are large and comparable in size (diameters of 19 and 14 km), with the remainder exhibiting a continuum of sizes in the range 2–7 km. The low measured ejection velocities suggest that gravitational re-accumulation after a collision may be a common feature of asteroid evolution. Moreover, these data can be used to check numerical models of larger-scale collisions8.

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We thank R. Binzel, C. Chapman, D. Durda, O. Eugster, B. Gladman, D. Hamilton, R. Jedicke, A. Morbidelli, F. Namouni and M. Sykes for their suggestions.

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  1. Southwest Research Institute, 1050 Walnut St, Suite 426, Boulder, Colorado, 80302, USA

    • David Nesvorný
    • , William F. Bottke Jr
    • , Luke Dones
    •  & Harold F. Levison


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The authors declare that they have no competing financial interests.

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Correspondence to David Nesvorný.

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