Chi-2

Its story

Chi-2 Orionis is a B2 blue supergiant, one of the standard stars by which astronomers have calibrated the whole class since 1943. Though at 1,802 light-years she looks only faintly bright, her intrinsic luminosity beats Rigel by almost a full absolute magnitude: without intervening dust she would dominate Orion. She pulses very softly as an Alpha Cygni variable, beating once every 2.87 days, almost imperceptibly.