Spin Rate of Asteroid 54509 (2000 PH5) Increasing Due to the YORP Effect.
P. A. Taylor, J.-L. Margot, D. Vokrouhlicky, D. J. Scheeres, P. Pravec,
S. C. Lowry, A. Fitzsimmons, M. C. Nolan, S. J. Ostro, L. A. M. Benner,
J. D. Giorgini, and C. Magri.
Science 316, 274-277.
Published online (Mar. 8, 2007)
DOI: 10.1126/science.1139038.
Abstract:
Radar and optical observations reveal that the continuous increase in the spin rate of near-Earth asteroid (54509) 2000 PH5 can be attributed to the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, a torque due to sunlight. The change in spin rate is in reasonable agreement with theoretical predictions for the YORP acceleration of a body with the radar-determined size, shape, and spin state of 2000 PH5. The detection of asteroid spin-up supports the YORP effect as an explanation for the anomalous distribution of spin rates for asteroids under 10 kilometers in diameter and as a binary formation mechanism.
Click here for a Cornell Chronicle news story (includes movie of the shape model).
Click here for more information about PH5 from Jean-Luc Margot (includes movies of the shape model).