Abstract
Images of comet Halley's nucleus taken by the HMC camera during the GIOT-TO encounter in 1986 show that a major part of the total dust production is localized in a few active areas which are the sources of gas-dust jets. The global dust distribution in the inner coma is dominated by two main jets roughly directed to the sun. A combination of a 1D thermal nucleus model with an axisymmetric continuum model of the jet outflow was used to investigate the properties of the inner coma. Detailed investigations show that the characteristics of the observed jets can be reproduced by outgassing from free sublimating active areas of a few km in diameter, a dust to gas ratio of 1–2.5 and a size distribution dominated by the larger grains. It is further shown that most of the observational constraints provided by the HMC data can be met simultaneously by a model of three jets superimposed on a weak background.
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Knollenberg, J., Kührt, E. & Keller, H.U. Interpretation of HMC images by a combined thermal and gasdynamic model. Earth Moon Planet 72, 103–112 (1996). https://doi.org/10.1007/BF00117509
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DOI: https://doi.org/10.1007/BF00117509