CCD PHOTOMETRY OF COMET-109P SWIFT-TUTTLE

We present results from post-perihelion CCD observations of 109P/Swift -Tuttle when it was at a heliocentric distance of 5.3 AU. From inspect ion of the image profiles, contamination from the coma is estimated to be 14%, and thus direct detection of the nucleus was achieved. From t he apparent magnitude we deduce a mean effective radius of r(e) = 11.8 km if an albedo of 4% is assumed. An upper mass limit of 7x10(18)g is obtained if we assume a density of 1 g cm(-3). We discuss the extent of active areas on the nucleus of 109P/Swift-Tuttle and estimate that similar to 3% Of the surface is active.