UBVRI photometry of 7 dwarfs in Alpha Per

The shape of the light curves suggests that the photometric variations are most often dominated by a single group of cool spots located at intermediate or high latitude on the stellar surface. Assuming that starspots are good tracers of the stellar magnetic field, the smooth light curves indicate the existence of a large scale, slowly varying magnetic structure at the surface of these ultrafast rotators.

For a description of the UBVRI photometric system, see e.g. <GCPD/08>