Speaker
Description
Many close-in exoplanets are expected to orbit inside the Alfvén surface of the stellar wind, the region where the stellar wind is dominated by the stellar magnetic field. In this scenario, the planet acts as an obstacle to the stellar wind flow, leading to an electromagnetic coupling between the star and the planet. The energy fluxes arising from this interaction can power enhanced emission in the stellar chromosphere, as observed in several systems. However, the exact physical mechanisms responsible for energy transfer remain uncertain.
Here, we present a study of magnetic star-planet interactions using 3D magnetohydrodynamic simulations of a magnetised hot Jupiter. The simulations incorporate stellar heating, tidal forces, and a magnetised stellar wind, providing the key physical ingredients needed to model these interactions self-consistently. Our simulations reveal the presence of Alfvén wings, which can carry a Poynting flux toward the star. We show that the size of the interaction region depends on the relative topology between the stellar wind field and the planetary field, with more aligned configurations producing larger Alfvén wings, while anti-aligned cases result in a weaker coupling.
Additionally, we provide scaling laws for the power generated by the interaction as a function of the planetary magnetic field strength, allowing for direct comparisons with analytical theories. These scaling relations offer a means to link observed star-planet magnetic interaction signals to planetary magnetic field strengths, providing a method to probe exoplanetary magnetism.
| Talk category | NOVA Network 2 |
|---|---|
| Preference for a talk or poster | Talk |
| Talk preference for PhD students | First year PhD |
