HR: 14:40h
AN: P23C-05    [Abstracts]
TI: The rotation of Saturn's auroral oval
AU: * Nichols, J
EM: jdn@bu.edu
AF: Center for Space Physics Boston University, 725 Commonwealth Avenue, Boston, MA 02215, United States
AU: Clarke, J
EM: jclarke@bu.edu
AF: Center for Space Physics Boston University, 725 Commonwealth Avenue, Boston, MA 02215, United States
AU: Cowley, S
EM: swhc1@ion.le.ac.uk
AF: Department of Physics and Astronomy University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
AU: Duval, J
EM: jduval@bu.edu
AF: Center for Space Physics Boston University, 725 Commonwealth Avenue, Boston, MA 02215, United States
AU: Wannawichian, S
EM: suwichaw@bu.edu
AF: Center for Space Physics Boston University, 725 Commonwealth Avenue, Boston, MA 02215, United States
AB: Near-planetary period oscillations have been observed in all explored regions of Saturn's magnetosphere, despite the fact that Saturn's magnetic and spin axes are closely co-aligned. In addition, the traditional measure of Saturn's rotation period, Saturn kilometric radiation (SKR), has been shown to vary over the timescale of months. We report that Saturn's southern auroral oval rotates with a radius of ~1° and period ~10.7 h, an unexpected result in a supposedly axisymmetric system. The implication of this new observation is either that it reveals the true dipole tilt of Saturn, in which case it represents the first direct observation of the rotation of Saturn's deep interior, or it indicates the presence of an external current system that produces an effect similar to a dipole tilt. Until we observe both poles simultaneously this will remain an ambiguity of the result. In either case, this work places an independent constraint on the dipole tilt of Saturn.
DE: 5706 Aurorae
DE: 5734 Magnetic fields and magnetism
DE: 5737 Magnetospheres (2756)
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting