EDP Sciences

Vol. 620
In section 1. Letters to the Editor

Direct evidence of a full dipole flip during the magnetic cycle of a sun-like star

by S. Boro Saikia, T. Lueftinger, S. V. Jeffers, C. P. Folsom, V. See, P. Petit, S. C. Marsden, A. A. Vidotto, J. Morin, A. Reiners, M. Guedel, and the BCool collaboration A&A 620, L11


Using spectropolarimetric observations, the authors have investigated the temporal evolution of the dipolar field of a sun-like star, the K dwarf 61 Cyg A. They have provided unprecedented sampling of the field over a single magnetic cycle of a star other than the Sun, and found that the behavior of the field during the cycle resembles the solar magnetic cycle. They show that 61 Cyg A has a dominant dipolar geometry except at chromospheric activity maximum. The dipole axis migrates from the southern to the northern hemisphere during the cycle. It is located at higher latitudes at chromospheric activity cycle minimum and mid-latitudes during cycle maximum. The dipole is the strongest at activity cycle minimum and much weaker at activity cycle maximum.