Rotation period of the O giant xi Persei: Coexistence of cyclic and periodic variability. A weakly magnetic candidate star
Researchers analyzed spectral lines from ξ Persei to find periodic signals in its wind, focusing on low-velocity regions. They discovered a consistent rotation period of 2.040514 days, suggesting a weak global magnetic field. This periodicity is linked to the changing projected area of a magnetospheric disc and points toward an undetected magnetic field structure.