Inhibition of the electron cyclotron maser instability in the dense magnetosphere of a hot Jupiter

Hot Jupiter (HJ) type exoplanets are expected to produce strong radio emission in the MHz range via the electron cyclotron maser instability (ECMI). To date, no repeatable detections have been made. To explain the absence of observational results, we conduct three-dimensional adaptive mess refinement (AMR) magnetohydrodynamic simulations of the magnetic interactions between a solar type star and Ill using the publicly available code PLUTO. The results are used to calculate the efficiency of the ECMI at producing detectable radio emission from the planets magnetosphere. We also calculate the frequency of the ECMI emission, providing an upper and lower bounds, placing it at the limits of detectability due to Earth's ionospheric cutoff of similar to 10 MHz. The incident kinetic and magnetic power available to the ECMI is also determined, and a flux of 0.069 mJy for an observer at 10 pc is calculated. The magnetosphere is also characterized and an analysis of the bow shock, which forms upstream of the planet, is conducted. This shock corresponds to the thin shell model for a colliding wind system. A result consistent with a colliding wind system. The simulation results show that the ECMI process is completely inhibited by the planets expanding atmosphere, due to absorption of UV radiation from the host star. The density, velocity, temperature and magnetic field of the planetary wind are found to result in a magnetosphere where the plasma frequency is raised above that due to the ECMI process making the planet undetectable at radio MHz frequencies.