Magnetic field topology of the RS CVn star II Pegasi (Kochukhov et al.)

Vol. 550
In section 7. Stellar structure and evolution

Magnetic field topology of the RS CVn star II Pegasi

by O. Kochukhov, M.J. Mantere, T. Hackman, and I. Ilyin A&A 550, A84

alt

The authors follow the long-term evolution of the magnetic field topology of the RS CVn binary star II Peg using an elaborate Zeeman-Doppler imaging approach and high-resolution circular polarization observations from the SOFIN spectropolarimeter at the Nordic Optical Telescope, covering 12 epochs spread over 7 years. They detect clear magnetic field signatures in average Stokes V profiles for all 12 data sets, corresponding to mean longitudinal fields of 50­-100 G. Magnetic inversions reveal evolving magnetic fields with typical local strengths of 0.5­-1.0 kG and complex topologies. The results suggest that the magnetic field is produced mainly by the turbulent alpha^2 dynamo rather than the solar alpha-omega dynamo.