Spectrophotometry and structural analysis of 5 comets

Abstract

We discuss the morphology and spectrophotometry of 5 comets visible in August, 2001. We decompose comae into coma profiles and azimuthally renormalized images, in which general and local features are quantitatively comparable. Comet 19P/Borrelly showed a strong gas fan toward the solar direction, but no detectable gas in the tail. Dust in its inner coma was collimated toward the antisolar direction and the tail, with no dust in the outer coma. The contribution of spatial variations structure was moderate, about 35%. Comet 29P Schwassmann-Wachmann 1 was observed in outburst: we detected ``spinning'' jet structures. A high level of dust production resulted in an unusually high Afρ=16600 cm. The spatial variations reached -77%, at the minimum, due in part to a jet and a ring-like structure in 1 arcminute distance from the nucleus. In comet C/2001 A2, we detected a strong post-perihelion increase of dust and gas activity, in which the C_2 profile became one magnitude brighter over a 3-day period. For comets C/2000 SV74 and C/2000 WM1, we present detailed pre-perihelion spectrophotometry and morphological information. Comet C/2000 SV74 showed high dust production (Afρ=1479 cm). Its coma suggests a steady-state outflow of material, while the low contribution of spatial variations support high level activity. The coma of C/2000 WM1 is dominated by solar effects, and CO+ forms the bulk of its gas activity. Despite its large heliocentric distance, we observed a nice tail.