HR: 14:30h
AN: P43A-03    [Abstracts]
TI: Does Dione have a tenuous atmosphere?
AU: * Khurana, K K
EM: kkhurana@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, Slichter Hall, University of California, Los Angeles, CA 90095, United States
AU: Burger, M H
EM: Matthew.Burger@gsfc.nasa.gov
AF: NASA-GSFC, Greenbelt, Maryland, United States
AU: Leisner, J S
EM: jleisner@ess.ucla.edu
AF: Institute of Geophysics and Planetary Physics, Slichter Hall, University of California, Los Angeles, CA 90095, United States
AU: Dougherty, M K
EM: m.dougherty@imperial.ac.uk
AF: Imperial College, Department of Physics, London, United Kingdom
AU: Russell, C T
EM: ctrussell@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, Slichter Hall, University of California, Los Angeles, CA 90095, United States
AB: Magnetic field observations collected from a close flyby of Dione by the Cassini spacecraft provide hints of a plasma-loading type interaction. The magnetic field lines drape around the moon and have a higher field strength upstream of the moon. Detailed modeling shows that this moon is a net contributor to the plasma in its vicinity. Even though the inferred mass-loading rates are quite small (< 7 gm/s), a detailed investigation shows that they cannot be explained from sputtering from the surface alone. The observations from Dione are in contrast to observations from Tethys and Rhea where the moons appear to absorb all the plasma incident upon them such that the wakes of these moons were observed to have enhanced field strengths and the magnetic field appeared to be drawn into the wakes from the flanks. The strength of ion-cyclotron waves observed in Saturn's magnetosphere also show an enhancement close to Dione's position indicating that the moon is a source of newly ionized plasma.
DE: 2732 Magnetosphere interactions with satellites and rings
DE: 6280 Saturnian satellites
SC: Planetary Sciences [P]
MN: 2007 Joint Assembly