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Z. Knezevic (Astronomical Observatory, Belgrade)
Presented are some new results regarding the motion of asteroids over time spans on the order of 108 Myr. First we discuss the comparison of proper elements for Trojan asteroids as computed by means of the semi analytic theory by Beauge and Roig and of the adapted synthetic theory by Milani. The overall agreement is good, but there are also differences, especially for the asteroids with large amplitude of libration. Next, we describe the results of an analysis of the reliability of computation of Maximum Characteristic Exponents of Lyapunov from the numerical integrations in the finite time intervals. We used two approaches, comparing the data computed for the same objects and starting from the same initial conditions. In one case we integrated the orbits for 1 Myr in the future and in the past and derived the corresponding differences, while in the other we compared the data computed from the integrations lasting 2 Myr, 10 Myr and 100 Myr. For about 80% of objects, the agreement of the results is better than the intrinsic accuracy of the procedure itself (determined by the ratio of the Lyapunov time and the integration time span). As expected, the largest differences were found for the most chaotic asteroids. Finally, we briefly discuss new determination of the coefficient of chaotic diffusion in the Veritas asteroid family region, computed over the sample of 112 family members, and the implications in terms of the probable young age of this family.
The author(s) of this abstract have provided an email address for comments about the abstract: zoran@aob.bg.ac.yu
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Bulletin of the American Astronomical Society, 36 #2
© 2004. The American Astronomical Soceity.