“A light that burns twice as bright burns half as long” – Dr. Eldon Tyrell

January 25, 2016

This week Hal tells us about Rigel, another beautiful star located in the Orion constellation.

Rigel - home of Kang & Kodos Credit Ivo Scheggia / nasa.gov
Rigel - home of Kang & Kodos

Many of the most beautiful stars in the sky appear in the winter for southern Colorado and northern New Mexico listeners. One of the most beautiful is the star Rigel, which makes up the lower right star in the constellation Orion. And, like Betelgeuse in the upper left corner of Orion, Rigel is a baby – only 8 to 10 million years old. 

But it’s a rather spoiled child. It’s been gobbling its food, in the form of hydrogen fusion, at a terrific rate, and it’s almost out. The surface of Rigel is around 22,000°F, more than twice as hot as our Sun. It’s at least 15 times as massive as our Sun, and it’s huge. If we swapped places with our Sun, it surface would be past the orbit of the planet Mercury.

But what is so striking in a telescope is the intense blue color. We tend to think of stars as white, but some of the most interesting ones are different colors, reflecting their temperature. Just like the hottest part of a match’s flame is blue, Rigel burns blue, with a brightness that is roughly 66,000 times brighter than our Sun. So, sunscreen people.

Over the next few million years, Rigel will expand and cool, becoming a red supergiant and, like Betelgeuse, will probably explode into a supernova, one of the most violent events in the cosmos.

At 800 light years away, Rigel is fairly distant from Earth, but because it burns so brightly, it’s the brightest star in the Orion, and the fourth brightest visible in the northern hemisphere.

And Rigel’s not alone out there. Like lots of stars, Rigel has two companions orbiting it. One of those companion stars is itself a binary system of two or more stars.

If you’d like to take a closer look at Rigel, or any of the other wonderful and amazing things in the sky, please visit KRCC.org or CSASTRO.org for a link to information on our monthly meetings and our free public star parties! 

This is Hal Bidlack for the Colorado Springs Astronomical Society, telling you to keep looking up, Southern Colorado!