Estimations of Maunder minimum solar irradiance and Ca II H and K fluxes using rotation rates and diameters

The total solar irradiance and Ca H and K fluxes (HK) for the Maunder minimum are estimated from scaling laws for solar-type stars using historical solar rotation rates and solar diameters. We found that the irradiance may be lower than modern solar minimum values by 1.23% in 1683 and by 0.37% in 1715. The estimate for 1683 is substantially lower than previously reported. Analysis of cosmogenic isotope records in ice cores and tree rings shows continuation of the Sun's magnetic cycle through the Maunder minimum; therefore, we find the HK fluxes to be 0.161 for 1683 and 0.163 for 1715, compared with the modern solar minimum flux value of similar to 0.164. This suggests that the Sun never reached a noncycling state.