Upper panel: light curve for star No. 485, a solar-mass star with (B − V)₀ = 0.664 in our sample. A periodicity of 6 − 7 d is evident from inspection of the light curve. Successive data points show that the photometry for this particular star is clearly repeatable at a level better than 0.01 mag. Our other solar-mass rotators have smaller amplitudes of variability. Lower panel: power spectrum for star No. 485, showing an unambiguous periodicity of the signal at P = 6.53 d, identified as the rotation period of the star.