CIPS Seminar 2/17

Wed, February 17, 2016

Francis Nimmo (UCSC) – "Tidal stresses and eruption activity on Enceladus"

 I'll discuss the general principles of tides, tidal stresses and tidal heating on synchronous satellites. I'll then go on to discuss specific applications at Enceladus, focusing in particular on the tidally-modulated eruptions observed to occur, how these might be explained, and what implications there are for subsurface structure.

Matthew Tiscareno (Cornell) – "Enceladus's measured physical libration requires a global subsurface ocean"

Previous investigations have shown that the plumes of Enceladus must be supplied by a liquid reservoir that is at least regional in extent. We used precision measurements of the surface of Enceladus over seven years of spacecraft observations to determine the satellite's precise rotation state, finding a forced physical libration that is too large to be consistent with Enceladus's core being rigidly connected to its surface. This implies the presence of a global ocean rather than a localized polar sea. We will discuss the rotational dynamics of Enceladus, the methods we used to determine the libration amplitude, and the implications of this discovery.