Kore: an open, fast, and efficient code to compute global eigenmodes in gas giant planets

The gas giant planets in our solar system can sustain global oscillations, i.e. modes, whose frequencies depend on the interior structure of the planet. These oscillations can be excited by the orbiting moons via tidal forces. The energy dissipated in this oscillatory motions can have a profound impact on the orbital evolution of the moons, much in the same way as the energy dissipated in the Earth's oceans makes our moon gradually recede. Thus, it is important to have both a qualitative and quantitative understanding of these global modes and their dependence on the interior structure of the planet. We present an efficient, fully spectral, numerical method to compute these global modes using the anelastic approximation. Here we showcase the possibilities of the code using simple structure models. However, our method is flexible enough to incorporate differential rotation and magnetic effects. We have made our code freely accessible, hoping it can become a useful tool for the planetary science community.