HR: 1330h
AN: P12A-1046    [PDF]
TI: JIMO Surface Composition Investigation of the Galilean Moons Via High-Resolution Analysis of Ejecta Dust Particles
AU: * Kruger, H
EM: harald.krueger@mpi-hd.mpg.de
AF: Max-Planck-institut f\"ur Kernphysik, Saupfercheckweg 1, Heidelberg, 69117 Germany
AB: Galileo in-situ dust measurements have shown that the Galilean moons are surrounded by tenuous dust clouds formed by collisional ejecta from their icy surfaces, kicked up by impacts of interplanetary micrometeoroids. The majority of the ejecta dust particles have been sensed at altitudes below five radii of these lunar-sized satellites. Average particle radii were between 0.5 and 1 micron, just above the detector threshold, indicating a size distribution decreasing towards bigger particles. The dust particles in the clouds consist of surface material from their parent bodies. They carry information about the properties of the surface from which they have been kicked up. In particular, these grains may carry organic compounds and other chemicals of biological relevance if they exist on the icy Galilean moons. In-situ analysis of the grain composition with a sophisticated dust analyzer instrument flying on a Jupiter Icy Moons Orbiter can provide important information about geochemical and geophysical processes during the evolutionary histories of these moons which are not accessible with other techniques from an orbiter spacecraft. Thus, spacecraft-based in-situ dust measurements can be used as a diagnostic tool for the analysis of the surface composition of the moons. This way, the in-situ measurements turn into a remote sensing technique by using the dust instrument like a telescope for surface investigation. An instrument capable of very high resolution composition analysis of dust particles is the Cometary Secondary Ion Mass Analyzer (COSIMA). The instrument has been built for ESA's comet orbiter Rosetta and is based on a high-resolution reflectron-type time-of-flight ion mass spectrometer.
DE: 5470 Surface materials and properties
DE: 6055 Surfaces and interiors
DE: 6062 Satellites
DE: 6094 Instruments and techniques
DE: 6218 Jovian satellites
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting