A possible explanation of the Blazhko effect in RR Lyrae.

Previous work has shown that an oscillating magnetic star always has significant non-radial motions at its surface. Here this result is incorporated into the oblique magnetic rotator model to produce the oscillating oblique magnetic rotator (OOMR). It is found that if the rotation is slow enough, the dynamics of the oscillating magnetic star are altered very little. However, the kinematic effect of the differing aspects of the oscillation presented to an observer at different epochs leads to modulated light and velocity curves. These are compared with the corresponding curves observed during the 41-day cycle of RR Lyrae and it is concluded that the OOMR is a plausible model for this star.