Secular variability of the longitudinal magnetic field of the Ap star γ Equ

We present an analysis of the secular variability of the longitudinal magnetic field B e in the roAp star γ Equ (HD 201601). Measurements of the stellar magnetic field B e were mostly compiled from the literature, and append also our 33 new B e measurements which were obtained with the 1-m optical telescope of Special Astrophysical Observatory (Russia). All the available data cover the time period of 58 years, and include both phases of the maximum and minimum B e. We determined that the period of the long-term magnetic B e variations equals 91.1 ± 3.6 years, with B e (max) = +577 ± 31 G and B e (min) = −1101 ± 31 G.