Rigel — also called Beta Orionis — is a blue supergiant located on the bottom part of the Orion Constellation. The star is the brightest in the constellation. Rigel is about 870 light-years away from our Sun. Since it’s a blue supergiant, it’s much larger and much hotter than our Sun.
Rigel is roughly 47,000 times more luminous, according to Encyclopedia Britannica. It is the seventh brightest star in the sky. According to Star Facts, “Even though it appears as a single star to the unaided eye, the Beta Orionis system consists of at least four components, designated Rigel A (or β Ori A), Rigel Ba, Rigel Bb and Rigel C. Rigel B and Rigel C are commonly referred to as Rigel BC.”
At roughly 8:30 in the evening, Rigel is located in the southwest of the sky. It’s not hard to miss, being the seventh brightest in the sky, it’s easy to see the bright blue ball above.
Absolute magnitude is the “true brightness” of a star. The Absolute magnitude is any star’s brightness at the distance of 10 parsecs. The absolute magnitude of Rigel is .12. The apparent magnitude is how bright the star is from the earth. The apparent magnitude of .5-.18. The apparent magnitude of our sun is -26.5 and the absolute magnitude is 4.8. Rigel is much brighter than the Sun on the absolute scale, around 40,000 times brighter than our Sun.
The spectral class of Rigel is B8I. Each B-8-I have specific meanings. The spectral classifications are decided by a spectrum. According to Harvard, “For the standard spectral types, the spectra are sorted into luminosity classes, and displayed in increasing sub-type (decreasing temperature) for each luminosity class.” “B,” means temperature. The spectrum of B is anywhere from 10,000–25,000K, and the numbers 0–9 are from hottest to coolest. 8 is on the cooler end of the spectrum. So, B8 is on the hotter side of the temperatures of stars, but on the cooler side of the B spectrum. “I” is more luminous than most on the spectrum, and “I” is normally set for supergiants such as Rigel.
Compared to the Sun — which is G2V — Rigel is much brighter and much hotter on the spectral scale.
The spectral scale is similar to that of the H.R. Diagram (Hertzsprung-Russell Diagram). It shows the luminosity and effective temperatures of stars. The supergiants, like Rigel, are in Class C. Those are high on the graph and extremely hot and large. The Sun, however, is in Class A, which is much cooler and smaller in the spectrum. Class A runs right through the middle of the graph.
According to Nine Planets, “The name Rigel is derived from Arabic, meaning leg or foot. It was named as such because of its location, representing Orion’s foot. It is also commonly known as Beta Orionis.”
Rigel dates back to roughly the 10th century when it was first said to be discovered, but it was first written about in the Alfonsine Tables of 1521.
There isn’t much about Rigel in mythology, but there is one story where Orwandil and his companion Norse-god Thor were walking across a river. His toe froze due to this trek, and according to legend, Thor broke off the toe, threw it in the sky and it became Orion’s toe-star.
Rigel is roughly eight million years old, which is quite young for a star. This star will only live for a few million more years. It will soon expand to a Red supergiant, which, at the end of its life, will explode into a supernova.
Unlike Rigel, the sun is billions of years old and will continue to shine for around 5 billion more years. We don’t need to worry about it exploding anytime soon, unlike that of Rigel.
When Rigel explodes into a supernova, it will become the second brightest body in the sky. Since it’s so far away, we don’t need to worry about this, and our future families will not need to worry but will have a great light show for a few weeks.
