Asteroid, Toutatis

Figure 5. Wavelength dependence of the polarization at a given phase angle (from [26]) a) Comet Hale-Bopp, for a equal 30, 40, 50 (fro m bottom to top) b) Asteroid Toutatis, for a equal to 20,30, 40,50 (fro m bottom to top).

Accurate shape models of near-Earth asteroids open the door to a wide variety of theoretical investigations that previously have been impossible or have used simplistic models (spheres or ellipsoids). For example, the Castalia and Toutatis models are being used to explore the stability and evolution of close orbits, with direct application to the design of robotic and piloted spacecraft missions, to studies of retention and redistribution of impact ejecta and to questions about plausible origins and lifetimes of... 

FIGURE 23 Toutatis s shape and non-principal-axis spin state from inversion of the images in Fig. 21a. The axes with no arrow tips are the asteroid s principal axes of inertia and the vertical arrow is its angular momentum vector the direction of the spin vector (the arrow pointing toward 11 o clock) relative to the principal axes is a (5.41 -day) periodic function. A flashlamp attached to the short axis of inertia and flashed every 15 min for 20 days would trace out the intricate path indicated by the small spheres stacked end-to-end the path never repeats. Toutatis s spin state differs radically from those of the vast majority of solar system bodies that have been studied, which are in principal-axis spin states. For those objects, the spin vector and angular momentum vector point in the same direction and the flashlamp s path would be a circle. 

Hudson, R. S., and Ostro, S. J. (1995). Shape and non-principal axis spin state of asteroid 4179 Toutatis, Science 270,84—86. 

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