The annual variation in the activity of the Geminid shower and the theory of the dispersal of meteoroid clusters

An intrinsic fluctuating component is found in the activity of the Geminid shower which is explained in terms of a number of distinct streamlets produced from the fragments of a disintegrated comet. Comparison with theory indicates that the particles in these streamlets were ejected uniformly round one orbit of the parent cometary fragment rather than close to perihelion and supports the notion of an insulating layer on the cometary surface. According to Monte Carlo simulations, of the order of 100 yr of observations are required to resolve the fine structure in the power spectrum of the shower activity. (author)