Distribution of the log(P_peak) estimates vs. log of the stellar rotation periods P for the solar-type stars with 5500 < T_eff < 6000 K. For comparison, the position of solar RTCs is indicated with a yellow circle which corresponds to P_peak = 154 days according to Rieger et al. (1984). The bar denotes the total range of solar RTCs according to Feng et al. (2017). The red line shows the linear regression of the lower border set of the log(P_peak) cluster, obtained for the minimum values of P_peak (red crossed squares) defined for the sequential ten intervals of P. The gray area in the lower right corner of the plot indicates the detection limit zone for P_peak, restricted by the Nyquist frequency (2P)⁻¹.