flare star

A dwarf M star that undergoes unpredictable outbursts lasting a few minutes, during which the brightness may increase by a magnitude or more. All flare stars have emission lines in their spectra and the flares are thought to be phenomena in the stellar chromosphere, similar to flares, but far more energetic. The nearest star to the Sun, Proxima Centauri, is a flare star. Flare stars are also known as UV Ceti stars.