HR: 1340h
AN: G43A-0793    [Abstracts]
TI: A new perturbation theory for fast rotators and a revised formula for spin axis precession
AU: * Varadi, F
EM: varadi@ucla.edu
AF: Institute of Geophysics and Planetary Physics, UCLA, 405 Hilgard Av., Los Angeles, 90095-1567 United States
AU: Moore, W B
EM: bmoore@ess.ucla.edu
AF: Institute of Geophysics and Planetary Physics, UCLA, 405 Hilgard Av., Los Angeles, 90095-1567 United States
AU: Moore, W B
EM: bmoore@ess.ucla.edu
AF: Earth and Space Sciences, UCLA, 405 Hilgard Av., Los Angeles, 90095-1567 United States
AB: A new approach to the dynamics of fast rotators (e.g., the Earth, Mars and certain asteroids) is introduced. First we demonstrate in a simple case that the commonly used equation for spin axis precession needs to be revised. When we use the full dynamical equations except for wobble terms, the rate of precession is inversely proportional to the equatorial moment of inertia and not the polar one. In the case of the Earth, the revised equation implies an adjustment of about one part in one thousand in the moments of inertia. The main part of the work is the derivation of a general perturbation theory which is based on Lie series on the Lie group of rotations and the elimination of fast rotation from the averaged system. The new theory yields the revised equation for spin axis precession, along with a consistent set of equations for all possible motions, either for rigid or deformable bodies. This theory will allow accurate, long-term integrations of orbital and rotational dynamics incorporating the physics of wobble and nutation in rapidly rotating bodies such as the Earth and Mars.
DE: 7504 Celestial mechanics
DE: 5450 Orbital and rotational dynamics
DE: 1227 Planetary geodesy and gravity (5420, 5714, 6019)
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting