Period versus dynamo magnetic field strength of the magneto-Rossby wave m = 1 spherical harmonics with n = 4 (red curve) and n = 3 (blue curve) plotted according to Eq. (43) from Gachechiladze et al. (2019). The equatorial angular velocity and plasma density in the dynamo layer are assumed to be Ω₀ = 2.8 × 10⁻⁶ s⁻¹ and ρ = 0.2 g cm⁻³, respectively. The observed periods in different data sets of the cycle 23 are marked by dots on the curves.