DDA 36th Meeting, 10-14 April 2005
Session 2 Orbits and Orbit Evolution I: from Small to Large
Oral, Monday, April 11, 2005, 9:35am-12:15pm

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[2.03] Direct Detection of the Yarkovsky Effect: Progress and Prognostications

S. R. Chesley, S. J. Ostro (JPL), D. Vokrouhlický (Charles Univ., Prague), J. D. Giorgini (JPL), D. Capek (Charles Univ., Prague), L. A. M. Benner (JPL), M. C. Nolan (NAIC), J. L. Margot (Cornell Univ.)

Following the first direct detection of the Yarkovsky effect on 6489 Golevka [1], attention has naturally turned to additional asteroids that might reveal this tiny acceleration in their motions. Preliminary calculations indicated that 2004 radar ranging to 4179 Toutatis would reveal the Yarkovsky acceleration [2]. That radar experiment was successful, but the final analysis shows that the uncertainty introduced by perturbations of numerous main belt asteroids with poorly determined masses overwhelms the otherwise significant Yarkovsky signal. This creates the unusual situation that the fidelity of an asteroid orbit estimation is limited by the fidelity of the force model, rather than by the quality of the observation set. Thus additional observations will not improve the situation and Toutatis appears unlikely to reveal unambiguous Yarkovsky acceleration in the foreseeable future. Even so, there remain a number of promising candidates for Yarkovsky detection in the next decade.

[1] Chesley et al. (2003) Science 302, 1739--1742.

[2] D. Vokrouhlický et al. (2005) Icarus 173, 166--184.

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Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.