H2O+, CO+, AND DUST IN COMET P SWIFT-TUTTLE

Comet P/Swift-Tuttle was observed in the light of H2O+, CO+ and contin uum with the 2-m telescope of the Bulgarian National Astronomical Obse rvatory (BNAO) on Nov. 25, 1992. We present column density maps of the H2O+ and CO+ ions and a map of the product of filling factor, geometr ical albedo, and phase function. The H2O+ ions are more concentrated t oward the nucleus than CO+. The ion distributions are in close agreeme nt with magnetohydrodynamic models including photochemistry of H2O+, C O+ and their parents. The color of a spiral dust jet present in the co ntinuum image was redder than the color of the ambient dust. The obser vations demonstrate the similarity between comets P/Halley and P/Swift -Tuttle.