Basic Information
Algol is one name (the Demon Star is another1) for a set of stars in the constellation Perseus. It's classified as an eclipsing binary, but technically it's three stars, a trinary system more properly known as Beta Persei A, B, and C. From earth, they look like a single star to the naked eye.
Beta Persei A is larger and brighter than the other two stars. A is a main sequence star, and B is a subgiant star. Their rotational plane is parallel to the Earth, so every few days A will eclipse B or vice versa. This results in Algol, as seen from earth, having variations in luminosity and color.
Algol is currently 92.8 light years from Earth. However, it was not always that far away. 7.3 million years ago, it passed within 9.8 light years of our planet. When that happened, it probably disrupted the Oort Cloud and sent a number of comets raining into our Solar System.
In the constellation of Perseus, Algol is supposed to represent the Gorgon's head; because the way it seems to vary in intensity is just too dang creepy.
See Also:
Algol Variables - the specific class of stars that is named after Algol.
Nemesis (Star) - for a discussion of how the close pass of other stellar bodies can pelt our solar system with comets
Sources
Game and Story Use
- The name "Demon Star" is probably just a reference to it's maddening variations in luminosity and color, caused by the frequent eclipses. However, that hasn't stopped sci-fi writers before, and neither should it stop you. You can't have a cool name like "Demon Star" and not have it mean something. It's gotta have Demons!
- The 1920s film Algol had a native of the planet have the demonic moniker Mephisto.
- In H.P. Lovecraft's short story Beyond The Wall of Sleep, Algol is the nemesis of the entity possessing Joe Slater.
- See also Hyperspace is a Scary Place - 'cause it's gotta be, at least when traveling near the Demon Star.