The effect of flares on total solar irradiance

Abstract

Flares are powerful bursts of energy released by relatively poorly understood processes that take place in the atmospheres of stars. However, although solar flares, from our own Sun, are the most energetic events in the solar system, in comparison to the total output of the Sun they are barely noticeable. Consequently, the total amount of radiant energy they generate is not precisely known, and their potential contribution to variations in the total solar irradiance incident on the Earth has so far been overlooked. In this work, we identify a measurable signal from relatively moderate solar flares in total solar irradiance data. We find that the total energy radiated by flares exceeds by two orders of magnitude the flare energy radiated in the soft-X-ray domain only, indicating a major contribution in the visible domain. These results have implications for our understanding of solar-flare activity and the variability of our star.