Magnetic effects in peculiar, pulsating stars

While the precise cause of pressure oscillations (p modes) in rapidly oscillating peculiar A (roAp) stars is under debate, the oscillations almost certainly depend on the stellar magnetic field. Only magnetic Ap stars exhibit p modes, and the pulsations have the same global symmetry as the magnetic field. We briefly review a range of magnetic effects in roAp stars. We discuss in more detail the possibility that magnetic oscillations may drive magnetosonic waves, observed as p modes. This idea can be tested by comparing frequencies of p mode oscillations in roAp stars of different masses and mean field strengths.