Long-Term Dynamical Evolution of the Minor Planet (4179) Toutatis

We have estimated the orbit of the minor planet (4179) Toutatis from 332 optical astrometric observations that span the period from 1934 to 1993. From this starting point, we have numerically integrated the orbit of Toutatis within the context of several dynamical models. Toutatis is currently in a 3:1 resonance with Jupiter and a weak.1:4 resonance with the Earth. We found the orbit of Toutatis to be extremely chaotic. However, the extreme degree of chaos found was due to the frequent close approaches to the terrestrial planets and not to the resonances. When the perturbations due to the terrestrial planets were included in the integration, the Lyapunov time was close to 50 years. Without the perturbations from the terrestrial planets the Lyapunov time was close to 10,000 years. Close approach distances and estimated uncertainties for all events that can be accurately predicted, based on the currently available astrometry, are presented. The closest approach to any terrestrial planet found in this study was to the Earth at a distance of 0.011 AU in 2004. The available astrometry does not support predictions beyond 2070 nor before 1407.