31st Annual Meeting of the DPS, October 1999
Session 70. Ganymede and Callisto
Contributed Oral Parallel Session, Friday, October 15, 1999, 10:30-12:00noon, Sala Pietro d'Abano

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[70.09] Dust Clouds surrounding the Galilean Satellites

H. Kr\"uger (MPIK, Germany), A. V. Krivov (St. Petersburg University, Russia), D. P. Hamilton (Univ. of Maryland, USA), E. Gr\"un (MPIK, Germany)

Dust clouds of the Galilean satellites Ganymede, Europa and Callisto have been detected in-situ with the Galileo dust detector. The dust grains have been sensed at altitudes below several satellite radii. We identify the particles originating from the satellites by their impact direction, impact velocity, and mass distribution. These data imply that the grains have been kicked up by hypervelocity impacts of micrometeoroids onto the satellites' surfaces. We calculate the radial density profile of the particles which would be ejected from the satellite by interplanetary and interstellar dust grains, assuming the yields, mass and velocity distributions of the ejecta obtained from laboratory impact experiments onto icy targets and considering the dynamics of the ejected grains. Dust measurements in the vicinities of satellites by spacecraft detectors are a beneficial tool to obtain more knowledge about the satellite surfaces, as well as dusty planetary rings maintained by satellites through the impact ejecta mechanism. Such an ejection process has been suggested as being responsible for maintaining both the Jovian ring and Saturn's E ring.


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The author(s) of this abstract have provided an email address for comments about the abstract: krueger@galileo.mpi-hd.mpg.de

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