Rigel is a star of the celestial north hemisphere, the star system is located in the constellation Orion. It has a visual magnitude of +0.18 and we find it about 860 light years from the Solar System. The main component is a white - blue giant of class B8. It is considered a triple system, in which the main star is orbited by two companions, Rigel B and C, whose distance between them is 28 AU, that revolve around Rigel A, a distance of the same of 2,000 UA . Rigel is also a variable star, with small oscillations in its brightness, a rare phenomenon in the supergiant. The range of variability ranges from 0.3 to 0.03 magnitude, between 3-30%, over a period of 25 days. A fourth star has been proposed in the system, but it is generally considered that the real reason lies in the physical pulsations of the surface of the main star.

Due to its luminosity, through a region of cloudiness, it should not be surprising that Rigel illuminates the clouds of dust that occur in its vicinity, the most notable of which is the Witch's Head Nebula. Rigel was classified by Johann Bayer (1603) with the name of Beta Orionis, putting it in second place. Why has the super red giant Betelgeuse stripped her of this honor? The truth is that Rigel is typically the brightest star, however, and Betelgeuse being a variable star, its luminosity becomes very occasionally greater than that of Rigel. Probably when Betelgeuse was named Alpha Orionis, it was because he was winning to Rigel in brightness. The two stars compete in being the brightest in our region of the Milky Way.

CHARACTERISTICS OF RIGEL

Compared with the Sun, it is estimated that Rigel has a mass 17 or 18 times greater. Its size can be measured directly and corresponds to a diameter equivalent to 73 soles. The temperature on its surface is 11,500 kelvin and as a consequence it is classified as a star of spectral type B8 (that is to say, it counts among the hottest stars of the Galaxy). Its luminosity (including non-visible light forms) is up to 85,000 times brighter than the Sun. In other words, if it were our star, life would be impossible on Earth (Even if we were as far away as Pluto).

More details here: Rigel

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