Three flares with blue continuum, one with a D3 preflare shell

Abstract

Three flares with short-lived flashes observed with a 65 A wide filter centered on 3835 A are discussed. Observations at other wavelengths indicated it is a 'blue continuum'; the flashes occur in pairs at the ends of flux loops and result from the precipitation of energetic particles. A shell of D3 absorption was observed in one of the flares, considered to be a compressed sheet of dense, hot material that limits the flare until it breaks out as a surge. It is concluded that the blue continuum may be the same as that seen in flare stars.