Rigel is the brightest star in the constellation Orion, taking the position of the hunter's left foot. It outshines the other named star in the constellation, Betelgeuse, ranking as the 6th most luminous star in our night sky. The name Rigel was passed down to us from Arabic astronomers; a shortening of the phrase rijl al-jauza, meaning Left Foot of the Central One.
The most striking characteristic of Rigel is how bright it is. From the Earth it appears so bright because it's relatively close to us at somewhere between 700 and 900 light years. On top of that, Rigel is one of the most intrinsically briilliant stars in this part of the galaxy. The closest more powerful star is Naos, 1,100 light years away in the Puppis constellation. Direct measurement of Rigel's diameter tells us that it has a radius about 78 times bigger than our Sun and shines about 66,000 times more intensely. Our knowledge of stellar evolution puts Rigel as a blue supergiant.
In its 10 million year lifetime, Rigel has been fusing hydrogen into helium at its core. At some point this inert helium core became too large to continue fusing, and the star started to swell and cool. Eventually Rigel will start to contract, and the helium core will get hot enough to start fusing. This helium flash will make the star swell up even bigger, turning it into a red supergiant. Elements in Rigel's core like carbon and neon will form until it finally explodes as a supernova. While it was thought that Rigel had a mass of 17 solar masses, certain observational and theoretical uncertainties make it possible that Rigel actually has a lower mass of around 14 solar masses. This would mean that the star is already fusing helium after already having been a red giant, and has shrunken down and heated its surface to return to its blue supergiant phase.