Fig. 3.

Evolution of the fluxes at 1 AU in different wavelength regimes (X-ray: 1–20 Å, long dashes; SXR: 20–100 Å, dashed line; EUV: 100–920 Å, dash-dotted line; FUV: 920–1180 Å, dotted line; Ly-α: 1200–1300 Å, grey solid line; UV: 1300–1700 Å, grey dashed line with diamonds) normalized to the present solar values. Power laws for the wavelength ranges were taken from Ribas et al. (2005). Line fluxes in the UV (1300–1700 Å) were summed up directly from observational data of strong emission lines (table 6 in Ribas et al., 2005).