The Rotation of Io

The gravitational force exerted by Jupiter on Io deforms the satellite and periodically changes its rotation. The gravitational interaction between Jupiter and Io in its precessing orbit also leads to the satellite having a small but finite obliquity. Both the tides and the rotation characteristics (librations and obliquity) depend on the interior structure of Io. Here we evaluate the rotation for various models of the interior of Io, which take into account observational constraints from magnetic induction observations and astrometry. In particular, we assess the signature of a magma ocean on the librations and obliquity. Since rotation is affected by the tides, we also examine the tidal Love numbers and their dependence on Io's interior properties.