Comparison of the dust distributions in the innermost comae of comets-1P/Halley and 19P/Borrelly spacecraft observations

Ho, T. -M.; Thomas, N.; Boice, D. C.; Combi, M.; Soderblom, L. A.; Tenishev, V.

Abstract:

We present a comparative study of the inner comae of comets 1P/Halley and 19P/Borrelly using data from the Halley Multicolour Camera (HMC) onboard Giotto and the Miniature Integrated Camera and Spectrometer onboard Deep Space 1 (DS1). We show that the dust brightness dependence as a function of radial distance is different for both comets. We suggest that optical depth or fragmentation effects dominate the brightness distribution at comet 1P/Halley whereas acceleration or non-point source geometry effects dominate at comet 19P/Borrelly. The nightside profiles of comet 19P/Borrelly suggest a continuing non-radial outflow from the nucleus out to several tens of kilometres. This modifies the observed dayside to nightside brightness ratio with distance and offers a further constraint on dust emission models. By setting up a linear system of equations to fit the dust intensity distribution, better fits could be obtained by incorporating acceleration into the equation of free-radial outflow. Finally, we estimate the dust production rate of 19P/Borrelly at the time of DS1 encounter as no higher than 324 kg/s based on comparisons with HMC intensity measurements. ?? 2007 Elsevier Ltd. All rights reserved.

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Article

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70029718

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Ho, T. -M.; Thomas, N.; Boice, D. C.; Combi, M.; Soderblom, L. A.; Tenishev, V.

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985

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7-8

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English

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Planetary and Space Science

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Comparison of the dust distributions in the innermost comae of comets-1P/Halley and 19P/Borrelly spacecraft observations; 2007; Article; Journal; Planetary and Space Science; Ho, T. -M.; Thomas, N.; Boice, D. C.; Combi, M.; Soderblom, L. A.; Tenishev, V.