Direct Detection of the Yarkovsky Effect by Radar Ranging to Asteroid 6489 Golevka
Steven R. Chesley,1*
Steven J. Ostro,1
David Vokrouhlick
,2
David 
apek,2
Jon D. Giorgini,1
Michael C. Nolan,3
Jean-Luc Margot,4
Alice A. Hine,3
Lance A. M. Benner,1
Alan B. Chamberlin1
Radar ranging from Arecibo, Puerto Rico, to the 0.5-kilometer
near-Earth asteroid 6489 Golevka unambiguously reveals a small
nongravitational acceleration caused by the anisotropic thermal
emission of absorbed sunlight. The magnitude of this perturbation,
known as the Yarkovsky effect, is a function of the asteroid's
mass and surface thermal characteristics. Direct detection of
the Yarkovsky effect on asteroids will help constrain their
physical properties, such as bulk density, and refine their
orbital paths. Based on the strength of the detected perturbation,
we estimate the bulk density of Golevka to be
grams per cubic centimeter.
2 Institute of Astronomy, Charles University, CZ-18000 Prague 8, Czech Republic.
3 Arecibo Observatory, National Astronomy and Ionosphere Center, Arecibo, PR 00612, USA.
4 Department of Earth and Space Sciences, University of California, Los Angeles, CA 90095, USA.
* To whom correspondence should be addressed. E-mail: steven.chesley{at}jpl.nasa.gov
