Can the low-Activity sun Become Dimmer at Maximum?

摘要

After analysing the ratio of sunspot to facular areas along the cycle for solar cycles 12 to 20 we propose two possibilities. One indicates a non-linear behaviour for low-activity cycles and a closer-to-linear behaviour for high-activity cycles, the other one presents a non-linear behaviour for both low- and high-activity cycles and a closer-to-linear behaviour for moderate-activity cycles. Furthermore, we also find within the cycle that during low-activity cycles the Sun becomes brighter as their magnetic activity level increases while for high-activity cycles the opposite occurs, in agreement with previous studies of solar-type stars; another possibility, however, is that when evolving from minimum to maximum both the low- and high-activity Sun may become fainter while the moderate-activity Sun brightens.