When one star equals four

There are lots of stars in the visible universe that stagger the imagination based on sheer size or mass, such as Betelguese or the Pistol Star (discovered in 1990 using the Hubble Space Telescope).

Others stars are fascinating for their awesome flaming gas streams, such as Beta Lyrae or for their odd pairings and strange orbital dances, such as Capella.

Capella was first recorded by the vanished Mesopotamian Akkadian culture in the 20th century B.C.

Let's take a look at Capella, also known by its astronomical name Alpha Aurigae, which turns out to be a complex system of four suns-not one. For those curious in name origins, the name capella is derived from the Latin vulgate meaning "she-goat". This star system's identification with a she-goat goes back through the mists of time.

Capella, which appears as a bright yellow star, is visible in the night sky right now (see accompanying sky map). It is the brightest star in the constellation Auriga, the Charioteer, and the third-brightest star seen in the northern sky-Arcturus and Vega are brighter.

Up until about the year 158,000 B.C., Capella was no. 1 in brightness in the northern night sky but thanks to changes in its magnitude in prehistory, Capella was pushed from the top of the heap.

When you gaze at Capella you are looking across a gulf 42 light years. The light you see from Capella today left its surface in the year 1967, the same year three brave Apollo 1 astronauts-Gus Grissom, Ed White, and Roger Chaffee-died in a fire on a Cape Canaveral launch pad and the same year astronomers discovered the first pulsars and gamma ray bursts in space.

One reason to explain Capella's exceptional brightness is the fact that the star we see from Earth is not a single sun, but four neighboring stellar objects made up of two binary pairs. So, Capella is, correctly, a four star system.

Vote on this Story by clicking on the Icon


Use the comment form below to begin a discussion about this content.

Sign in to comment