HR: 14:55h
AN: P23C-06 INVITED    [Abstracts]
TI: Saturn's Variable Radio Period
AU: * Lecacheux, A
EM: alain.lecacheux@obspm.fr
AF: Observatoire de Paris, LESIA Observatoire de Meudon, Meudon, 92190, France
AB: Latest SKR measurements by Cassini/RPWS confirm the observed, slow and regular increase of its rotational modulation period (~10.9 hr), at the scale of about 0.5 percent over the last three years. In the meantime, similar drifts could also be find in some other observed magnetospheric phenomena (e.g. magnetic field, UV auroras, etc…), indicating that the inner magnetosphere of Saturn is globally changing at the 30-year scale of its revolution around the Sun. Refined analyses of individual SKR radio components (Kurth et al. (2007), Gurnett et al. (this session)) suggest that different regions of the inner magnetosphere might correspond to different apparent periods, all of them being substantially larger than the internal rotation period of 10.543 hr, determined from the measured planetary gravity field (Anderson and Schubert (2007)). We further discuss the constraints brought by SKR observations on spin modulated phenomena in Saturn's environment and, more particularly, address the question of the nature of the SKR rotational modulation, i.e. a pulsing source of radio emission (blinking light) versus a rotating disturbance (searchlight).
DE: 5734 Magnetic fields and magnetism
DE: 6275 Saturn
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting