Variations in activity of the sun and stars of the late spectral types on different timescales

The variations in different (7–21 years) activity periods (F10.7) in the atmospheres of stars of the late spectral types (G2–K5) and the Sun have been considered. F10.7 quasiperiodic oscillations with periods varying from 1.8 to 12.5 years have been detected. The oscillation amplitudes account for ~20% of the amplitude of the long-term cycle maximum. It has been found that the logarithm of quasiperiodic oscillations correlates well (r = 0.900 ± 0.051) with the period of the long-term activity cycle.