Betelgeuse: Facts & Size

Instructor: Katie Chamberlain

Katie has a PhD in Microbiology and has experience preparing online education content in Biology and Earth Science.

You don't need a super giant brain to learn about this red supergiant star. Betelgeuse, of the Orion constellation, won't be around forever; so, play it safe and learn about it now.


There are many types of stars: movie stars, throwing stars, gold stars, and of course, the stars in the sky. One of the more famous stars is Betelgeuse (which is pronounced 'beetle juice'), or Alpha Orionis. Betelgeuse is partly famous because of its interesting name, and partly famous because of its location in the recognizable constellation Orion.

The constellation Orion. Betelguese is the reddish star in the upper left
The Constellation Orion

Orion, the hunter, is easily recognized by the line of three stars which forms his belt. To the upper left of the belt is the star Betelgeuse, which represents the hunter's raised arm. The name Betelgeuse is a sloppy translation from the Arabic words for 'hand of the giant.' It was also the source of inspiration for Michael Keaton's character name in the movie 'Beetlejuice.'

Betelgeuse is a red supergiant star located approximately 520 light years from Earth. Red supergiants are a rare type of star - only 200 have been identified in our galaxy. This classification tells us quite a few things about Betelgeuse's age, size, appearance, and eventual demise.


During the main sequence life of a star, gravity causes hydrogen to fuse to form helium in the star's core. However, when the hydrogen runs out and the helium accumulates, the game changes. Large stars like Betelgeuse will swell to a massive size, hence their supergiant status.

Larger stars tend to burn their hydrogen more quickly, and thus have shorter lifespans. For example, Betelgeuse is at the end of its life, even though it is only about ten million years old. Our sun is still in its prime at nearly five billion years old.

Appearance and Size

Betelgeuse is the second brightest star in Orion, and one of the ten brightest stars in the entire sky. It is typically described as having a ruddy red appearance, which is particularly evident when comparing it to the blue glow of Rigel (the lower right star of Orion).

Although Betelgeuse is actually cooler than our sun, it is about 10,000 times brighter. Its brightness can vary slightly due to changes in its size, but it is easily visible in the Southern sky during the winter months to observers in the Northern hemisphere.

Betelgeuse photographed by the Hubble telescope
Betelgeuse photographed by the Hubble telescope

To unlock this lesson you must be a Study.com Member.
Create your account

Register for a free trial

Are you a student or a teacher?
I am a teacher

Unlock Your Education

See for yourself why 30 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back

Earning College Credit

Did you know… We have over 95 college courses that prepare you to earn credit by exam that is accepted by over 2,000 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it free for 5 days!
Create An Account