Detection of Rotational Acceleration of Bennu Using HST Light Curve Observations

M. C. Nolan, E. S. Howell, D. J. Scheeres, J. W. McMahon, O. Golubov, C. W. Hergenrother, J. P. Emery, K. S. Noll, S. R. Chesley, D. S. Lauretta

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


We observed the near-Earth asteroid (101955) Bennu from the ground in 1999 and 2005, and with the Hubble Space Telescope (HST) in 2012, to constrain its rotation rate. The data reveal an acceleration of 2.64 ± 1.05 × 10 −6  deg/day 2 , which could be due to a change in the moment of inertia of Bennu or to spin up from the Yarkovsky-O'Keefe-Radzievskii-Paddack effect or other source of angular momentum. The best solution is within 1 σ of the period determined by Nolan et al. (2013, The Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission will determine the rotation state independently in 2019. Those measurements should show whether the change in rotation rate is a steady increase (due, e.g., to the Yarkovsky-O'Keefe-Radzievskii-Paddack effect) or some other phenomenon. The precise shape and surface properties measured by the OSIRIS-REx science team will allow for a better understanding of variations in rotation rate of small asteroids.

Original languageEnglish (US)
Pages (from-to)1956-1962
Number of pages7
JournalGeophysical Research Letters
Issue number4
StatePublished - Feb 28 2019
Externally publishedYes


  • Bennu
  • Hubble Space Telescope
  • YORP
  • asteroids

ASJC Scopus subject areas

  • Geophysics
  • General Earth and Planetary Sciences


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