THE DUST TAIL OF COMET WILSON 1987VII

We discuss the analysis of three plates secured with the ESO Schmidt telescope concerning the dust tail of Comet Wilson 1987VII which were used as input for the inverse numerical approach to the interpretation of comet dust tails (Fulle 1989). We consider dust grains of diameters between 10 μM and 5 cm ejected during the time interval - 600<t< - 30 (days related to perihelion) and obtain a total dust mass of (4 ± 2) 1014 g [for an albedo for the phase function Ap(α) = 0.02, 43°<α51°, Newburn and Hanner (1989)] and a power index of the time-averaged size distribution of - 3.0 ± 0.1. The size distribution is about constant in time. The dust mass-loss rate reaches a broad maximum of ≈107 g s-1 at t≈ - 120.