Dust production from collisions in extrasolar planetary systems The inner (beta) Pictoris disc

Light curves and images of 67P/Churyumov-Gerasimenko are presented for the 2002-2003 apparition based on amateur CCD monitoring using a standardised method to produce consistent photometry in Johnson-Kron-Cousins system. Multiaperture data shows a large outburst at perihelion during which dust production increased by a factor of 2 to give a peak value of Af(rho) (almost equal)350 cm. A similar outburst was seen at the same epoch of the previous apparition in 1995-96 and probably in 1982-83, suggesting that the light curve is similar at succesive returns. A considerable change is seen in the slope of the light curve at r=1.85 AU ( T+140 days) corresponding to a second significant increase in dust production. Overall though the dust production shows a very steep dependence with heliocentric distance, falling as r^(-5.8).