A micrometeorite erosion model and the age of Saturn's rings

An erosional model of Saturn's rings is proposed based on theoretical studies of the high charge-to-mass ratio particles in Saturn's ring plane, and assuming that the B and C rings were initially formed as one ring with the optical thickness of the present B ring. The erosion rate is calculated using data from observed micrometeorite fluxes, and a ring age of 4.4-76 Myr is determined which is inconsistent with the 4.5-Gyr ring lifetime required by the cosmogonic ring hypothesis. The sharpness of the transition between the B and C rings suggests that the principal mass loss is through particles moving at a few m/sec with respect to the parent bodies from which they were eroded.