Variations in solar luminosity

The roles of evolution and episodic mixing in determining the solar luminosity are discussed. The influence of perturbations in the convection zone on the luminosity is reviewed in detail, showing that the efficiency of convection has significant effects on both the luminosity and the radius. The amplitude of the change is strongly dependent on the time scale of the perturbation. In the superadiabatic zone and photosphere, the effects of local suppression of convection efficiency are visible in the form of sunspots. Empirical data on solar irradiance obtained from space-borne radiometers have demonstrated the effect of sunspots on irradiance and have led to the tentative conclusion that the flux blocked by the spots is stored for very long times. 210 references