The OSIRIS-REx target asteroid (101955) Bennu: Constraints on its physical, geological, and dynamical nature from astronomical observations

    Authors

    D. S. Lauretta; A. E. Bartels; M. A. Barucci; E. B. Bierhaus; R. P. Binzel; W. F. Bottke; H. Campins; S. R. Chesley; B. C. Clark; B. E. Clark; E. A. Cloutis; H. C. Connolly; M. K. Crombie; M. Delbo; J. P. Dworkin; J. P. Emery; D. P. Glavin; V. E. Hamilton; C. W. Hergenrother; C. L. Johnson; L. P. Keller; P. Michel; M. C. Nolan; S. A. Sandford; D. J. Scheeres; A. A. Simon; B. M. Sutter; D. Vokrouhlicky;K. J. Walsh

    Comments

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    Abbreviated Journal Title

    Meteorit. Planet. Sci.

    Keywords

    NEAR-EARTH ASTEROIDS; 1999 RQ(36); RADAR; SURFACE; YARKOVSKY; ITOKAWA; BELT; LIGHTCURVE; MAGNITUDE; FAMILIES; Geochemistry & Geophysics

    Abstract

    We review the results of an extensive campaign to determine the physical, geological, and dynamical properties of asteroid (101955) Bennu. This investigation provides information on the orbit, shape, mass, rotation state, radar response, photometric, spectroscopic, thermal, regolith, and environmental properties of Bennu. We combine these data with cosmochemical and dynamical models to develop a hypothetical timeline for Bennu's formation and evolution. We infer that Bennu is an ancient object that has witnessed over 4.5Gyr of solar system history. Its chemistry and mineralogy were established within the first 10Myr of the solar system. It likely originated as a discrete asteroid in the inner Main Belt approximately 0.7-2Gyr ago as a fragment from the catastrophic disruption of a large (approximately 100-km), carbonaceous asteroid. It was delivered to near-Earth space via a combination of Yarkovsky-induced drift and interaction with giant-planet resonances. During its journey, YORP processes and planetary close encounters modified Bennu's spin state, potentially reshaping and resurfacing the asteroid. We also review work on Bennu's future dynamical evolution and constrain its ultimate fate. It is one of the most Potentially Hazardous Asteroids with an approximately 1-in-2700 chance of impacting the Earth in the late 22nd century. It will most likely end its dynamical life by falling into the Sun. The highest probability for a planetary impact is with Venus, followed by the Earth. There is a chance that Bennu will be ejected from the inner solar system after a close encounter with Jupiter. OSIRIS-REx will return samples from the surface of this intriguing asteroid in September 2023.

    Journal Title

    Meteoritics & Planetary Science

    Volume

    50

    Issue/Number

    4

    Publication Date

    1-1-2015

    Document Type

    Article

    Language

    English

    First Page

    834

    Last Page

    849

    WOS Identifier

    WOS:000352625200018

    ISSN

    1086-9379

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