LAM seminar: Laurent Lamy

The (spring) magnetosphere of Uranus probed by a decade of HST observations of its ultraviolet aurorae

The re-detection and long-term monitoring of the ultraviolet aurorae of Uranus with the Hubble Space Telescope during the past decade has provided a new, so far unique, mean to remotely investigate from Earth the asymmetric magnetosphere of Uranus since its discovery by Voyager 2, while waiting for a future orbital mission. Various spectro-imagers have been used to collect instantaneous images and spectra of the aurorae and of the underlying atmosphere in the Far UV range under variable solar and solar wind conditions. The observations were obtained through a series of programs executed between 2011 and 2023, aimed at sampling various timescales ranging from a fraction of a planetary rotation (~17.24h) up to seasons. This time interval provided the opportunity to sample radically different magnetosphere/solar wind configurations between equinox and solstice. In this presentation, we review the properties of the auroral and airglow emissions, in terms of spatial distribution, energy budget, dynamics and new constraints brought onto the internal rotation period. We highlight how these results will help to prepare the observations to be acquired in orbit from a Uranus orbiter.

Important : If enough time, the seminar will be followed by a 3D projection of movie of the terrestrial polar (borealis and australis) aurorae in the LAM amphitheater.