@article{71f9cbdfad3f45a491db5edd4e640446,
title = "Detection of Rotational Acceleration of Bennu Using HST Light Curve Observations",
abstract = " 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, https://doi.org/10.1016/j.icarus.2013.05.028). 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. ",
keywords = "asteroids, Bennu, Hubble Space Telescope, OSIRIS-REx, YORP",
author = "Nolan, {M. C.} and Howell, {E. S.} and Scheeres, {D. J.} and McMahon, {J. W.} and O. Golubov and Hergenrother, {C. W.} and Emery, {J. P.} and Noll, {K. S.} and Chesley, {S. R.} and Lauretta, {D. S.}",
note = "Funding Information: We thank S. Lowry and an anonymous reviewer for helpful comments that improved this paper. This study is based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5‐26555. These observations are associated with program 13118. The HST data are presented in Data Set S1, and the raw images are available from the Hubble Legacy Archive. The work of S. R. C. was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The work of J. W. M. was supported by the National Aeronautics and Space Administration under Grant NNX14AN13G issued through the Planetary Geology and Geophysics Program. This material is based upon work supported by NASA under Contract NNM10AA11C issued through the New Frontiers Program. Funding Information: We thank S. Lowry and an anonymous reviewer for helpful comments that improved this paper. This study is based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program 13118. The HST data are presented in Data Set S1, and the raw images are available from the Hubble Legacy Archive. The work of S.?R.?C. was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The work of J.?W.?M. was supported by the National Aeronautics and Space Administration under Grant NNX14AN13G issued through the Planetary Geology and Geophysics Program. This material is based upon work supported by NASA under Contract NNM10AA11C issued through the New Frontiers Program. Publisher Copyright: {\textcopyright}2019. American Geophysical Union. All Rights Reserved.",
year = "2019",
month = feb,
day = "28",
doi = "10.1029/2018GL080658",
language = "English (US)",
volume = "46",
pages = "1956--1962",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "4",
}