Betelgeuse (from Arabic: إبط الجوزاء Ibṭ al-Jauzā’, meaning "the armpit of Orion") is a large red supergiant star in the Orion constellation. It is usually the ninth-brightest star in the night sky, and the second-brightest in Orion.
Betelgeuse is a semiregular variable star whose apparent magnitude varies between 0.2 and 1.2. This is the widest range of any first-magnitude star.