Hot Spot Offset Variability from Magnetohydrodynamical Thermoresistive Instability in Hot Jupiters

Raphaël Hardy ( Université de Montréal )

Hot Jupiter atmospheres are possibly subject to a thermoresistive instability. Such an instability may develop as the ohmic heating increases the electrical conductivity in a circular feedback loop, which ultimately leads to a runaway of the atmospheric temperature. We introduce a simplified longitudinally extended one-dimensional radial model of the equatorial plane of a hot Jupiter. We represent the temperature and magnetic diffusivity as a first order Fourier approximation in the longitudinal direction. With this feature of the model, we are able to predict the hot spot offset during the unfolding of the thermoresistive instability and following Alfvénic oscillations. We show a representative simulation undergoing the thermoresistive instability, in which the peak flux offset varies between 34 degrees eastward to 24 degrees westward. Therefore, this thermoresistive instability should be an observable feature of hot Jupiters, given the right timing of observation and physical properties of the planet.