Tracking the Uranian magnetosphere between solstice and equinox and the inner rotation rate of the planet
Abstract
This proposal aims at bringing our understanding of the Uranian magnetosphere, as the archetype of twin ice giant asymmetric magnetospheres, a step forward before the end of HST lifetime. We propose to track the UV (H and H2) aurorae of Uranus with STIS imaging at next opposition, while the planet lies between equinox and solstice. The observations will be carefully scheduled to sample variable solar wind conditions predicted by robust MHD codes throughout a validated methodology. The aurorae, predicted to be brighter and more spatially elongated than near equinox, will sample the ununderstood equinox-to-solstice configuration of the Uranian magnetosphere and the dynamical evolution from equinox to northern winter solstice. Such observations are crucial to resample and update the inner planetary rotation rate, a key parameter for understanding the planetary interior, and to define a valid SIII longitude system which will be required for any future spatial exploration of the planet. For this purpose, the aurorae will be accurately fitted by magnetic field models and cross-compared to the position of the magnetic poles derived previously to constrain the rotation rate at unprecedented accuracy.
- Publication:
-
HST Proposal
- Pub Date:
- May 2020
- Bibcode:
- 2020hst..prop16313L