Title

Shape of (101955) Bennu indicative of a rubble pile with internal stiffness

Authors

O. S. Barnouin, Johns Hopkins University Applied Physics Laboratory
M. G. Daly, York University, Centre For Research in Earth and Space Science
E. E. Palmer, Planetary Science Institute
R. W. Gaskell, Planetary Science Institute
J. R. Weirich, Planetary Science Institute
C. L. Johnson, Planetary Science Institute
M. M. Al Asad, The University of British Columbia
J. H. Roberts, Johns Hopkins University Applied Physics Laboratory
M. E. Perry, Johns Hopkins University Applied Physics Laboratory
H. C.M. Susorney, The University of British Columbia
R. T. Daly, Johns Hopkins University Applied Physics Laboratory
E. B. Bierhaus, Lockheed Martin Corporation
J. A. Seabrook, York University, Centre For Research in Earth and Space Science
R. C. Espiritu, Johns Hopkins University Applied Physics Laboratory
A. H. Nair, Johns Hopkins University Applied Physics Laboratory
L. Nguyen, Johns Hopkins University Applied Physics Laboratory
G. A. Neumann, NASA Goddard Space Flight Center
C. M. Ernst, Johns Hopkins University Applied Physics Laboratory
W. V. Boynton, The University of Arizona
M. C. Nolan, The University of Arizona
C. D. Adam, KinetX Aerospace, Inc.
M. C. Moreau, NASA Goddard Space Flight Center
B. Rizk, The University of Arizona
C. Y. Drouet D’Aubigny, The University of Arizona
E. R. Jawin, Smithsonian National Museum of Natural History
K. J. Walsh, Space Science and Engineering Division
P. Michel, Observatoire de la Côte d'Azur
S. R. Schwartz, The University of Arizona
R. L. Ballouz, The University of Arizona
E. M. Mazarico, NASA Goddard Space Flight Center
D. J. Scheeres, University of Colorado Boulder
J. W. McMahon, University of Colorado Boulder
W. F. Bottke, Space Science and Engineering Division

Document Type

Article

Publication Date

4-1-2019

Abstract

© 2019, The Author(s), under exclusive licence to Springer Nature Limited. The shapes of asteroids reflect interplay between their interior properties and the processes responsible for their formation and evolution as they journey through the Solar System. Prior to the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) mission, Earth-based radar imaging gave an overview of (101955) Bennu’s shape. Here we construct a high-resolution shape model from OSIRIS-REx images. We find that Bennu’s top-like shape, considerable macroporosity and prominent surface boulders suggest that it is a rubble pile. High-standing, north–south ridges that extend from pole to pole, many long grooves and surface mass wasting indicate some low levels of internal friction and/or cohesion. Our shape model indicates that, similar to other top-shaped asteroids, Bennu formed by reaccumulation and underwent past periods of fast spin, which led to its current shape. Today, Bennu might follow a different evolutionary pathway, with an interior stiffness that permits surface cracking and mass wasting.

Publication Name

Nature Geoscience

Volume Number

12

First Page

247

Last Page

252

Issue Number

4

DOI

10.1038/s41561-019-0330-x

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