Total energy release inside a Moon-sized planet orbiting a WD at various orbital distances. Energy release was determined by the inclination of the stellar dipole axis. The shaded area marks the region inside the Roche limit of approximately 0.006 au. One can see the co-rotation point at around 0.003 au, where induction heating is not efficient. For a short stellar rotation period of 2 h, the co-rotation region is inside the Roche limit; however, for longer rotation periods, it is located further from the star.