What is Rigel?
[[File:Rigel_blue_supergiant.jpg|thumb|250px|Rigel viewed from 1 au, picture taken in [[Celestia]].]] [[File:Orion constellation map.svg|thumb|right|250px|The Orion constellation]] '''Rigel''' is a hot supergiant [[star]] in the [[Milky Way]] galaxy. It is a blue-white [[supergiant]]. It is in the [[constellation]] [[Orion (constellation)|Orion]]. Rigel is much larger than our Sun. It is 78 times the [[Sun]]'s radius, with a [[diameter]] of more than 100 million kilometers, but it's mass is 21 times more massive than our sun. It's a temperature of 12100 Kelvin, which causes the star to glow about 120 000 times brighter than the Sun. <ref>{{cite web|title=Rigel (Beta Orionis) Facts: Size, Mass, Luminosity, Name, Orion |url=https://www.star-facts.com/rigel/ |website=Star Facts |date=17 September 2019 |publisher=admin |accessdate=September 17, 2019}}</ref>Rigel is 864 light-years (8.2 quadrillion km) from Earth in Orion. Because it is near the [[equator]], Rigel is seen from Earth as a small, bluish circle on clear nights from both hemispheres. ==Stellar system== Rigel appears to be as a single star, but in fact it's a stellar system of at least four stars. That include Rigel A, Rigel Ba, Rigel Bb and Rigel C. Rigel Ba and Bb orbits around each other every 9.8 days, while Rigel C orbits around Rigel B binary every 63 years. The distance from Rigel A and BC is ~2 200 AU, so the [[orbital period]] of each other is ~24 000 years. Rigel Ba, Bb and C have a mass of 3.84; 2.94; and 3.84 solar masses, and therefore they're B-type main sequence stars.<ref>{{cite web|title=Rigel (Beta Orionis) Facts: Size, Mass, Luminosity, Name, Orion |url=https://www.star-facts.com/rigel/ |website=Star Facts |date=17 September 2019 |publisher=admin |accessdate=September 17, 2019}}</ref> ==Fate== Rigel pulsates.<ref>{{cite web|title=Rigel (Beta Orionis) Facts: Size, Mass, Luminosity, Name, Orion |url=https://www.star-facts.com/rigel/ |website=Star Facts |date=17 September 2019 |publisher=admin |accessdate=September 17, 2019}}</ref> The