Precession of triaxial cometary nuclei

Comet nuclei are modeled as rotating, homogeneous, triaxial ellipsoids that precess during perihelion passage due to a subsolar dust and gas jet induced by solar heating. We develop a phase-averaged system of equations in which the torque is averaged over a rotation about the spin axis. The inertial space precession of the rotation axis is computed numerically using the phase-averaged system. The result is checked against independent calculations using the exact Euler-Poisson system of equations.