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How global faculae and network coverage relates to that of sunspots isrelevant to the brightness variations of the Sun and Sun-like stars. We extendearlier studies that found the facular-to-sunspot-area ratio diminishes withtotal sunspot coverage. Chromospheric indices and the total magnetic fluxenclosed in network and faculae, referred to here as 'facular indices', aremodulated by the amount of facular and network present. We probed therelationship between various facular and sunspot indices through an empiricalmodel that takes into account how active regions evolve. This model wasincorporated into a total solar irradiance (TSI) model. The model presentedhere replicates most of the observed variability in the facular indices, and isbetter at doing so than earlier models. Contrary to recent studies, we foundthe relationship between the facular and sunspot indices to be stable over thepast four decades. The model indicates that, like the facular-to-sunspot-arearatio, the ratio of the variation in chromospheric emission and total networkand facular magnetic flux to sunspot area decreases with the latter. The TSImodel indicates the ratio of the TSI excess from faculae and network to thedeficit from sunspots also declines with sunspot area, with the consequencebeing that TSI rises with sunspot area more slowly than if the two quantitieswere linearly proportional to one another. The extrapolation of the TSI modelto higher activity levels indicates that in the activity range where Sun-likestars are observed to switch from growing brighter with increasing activity tobecoming dimmer instead, the activity-dependence of TSI exhibits a similartransition as sunspot darkening starts to rise more rapidly with activity thanfacular brightening. This bolsters the interpretation of this behavior ofSun-like stars as the transition from a faculae-dominated to a spot-dominatedregime.

How faculae and network relate to sunspots, and the implications for solar and stellar brightness variations