Sketch of the geometry used to compute the theoretical light curve of an auroral ring on AU Mic. The source of the emission is assumed to be due to the electron cyclotron maser instability (ECMI) in a ring-like configuration as what is seen on Jupiter. Since ECMI is beamed, only a fraction of the auroral ring is visible at any given time. Depending on the geometry, the fraction visible changes as a function of time, modulating the relative brightness of the ring.