The central character in my lawman novels is, by training, an astronomer. He often talks about telescopes, and viewing things in the sky. So far, at least, he’s never mentioned Double Stars.

In real life, they’re one of my favorite things to look at.

The most famous double star most folks are aware of is the FICTIONAL double star that Tatooine, the planet Luke Skywalker grew up on. The spectacular scene of the star set in Star Wars 4 – A New Hope is breath taking.

A double star is defined as two stars that orbit around a common center of gravity. They are gravitationally bound to each other. Of course there’s stars out there that have more than one companion, the most famous of which is the star nearest us, Alpha Centauri. there’s three suns there, one of which is small red dwarf called Proxima Centauri which is closest star to us, but not by much. It orbits the other two stars.

Alpha Centauri A & B. Proxima Centauri is not in this picture.

But the heavens are full of double stars. Some very similar, some very oddly matched. Most stars have a companion star. Our Sun is an oddity in that it doesn’t, but there is a theory floating about that in the distant past (like about the time the planets were forming), we had a companion. But it was pulled away and is lost to us in the past. Some astronomers believe this explains the oddity of objects in the distant parts of the solar system. Where our ex-companion is now is anyone’s guess.

There’s several kinds of double stars.

One is called a “Visual Double.” Often times they aren’t really double stars. They’re just two stars that happen to be in the same direction. An example is the star Mizar in the handle of the Big Dipper. The ancient Arabs used the star as a test of eyesight, which I find odd. Even with my old eyes and need for glasses, I can still see the two stars.

If you look at Mizar, you see the star in the bend, and next to it is a slightly fainter “partner” star. The name of this star is Alcor. But it’s not a true double. The fainter star just happens to lie in the general direction of Mizar and are actually separated by dozens of light years.

Mizar and Alcor

Mizar really is a Multi-Star system (six stars actually), but some are orbiting very close to each other, and some are faint. It takes a decent telescope and some other tools to split the actual star Mizar apart so you can see the companions.

Sirius A and B as taken using the Hubble Space Telescope

I mentioned earlier that stars are often very mismatched. Sirius, the brightest star visible in the Northern Hemisphere is an example. We have the star we see, but it has a faint companion we call a white dwarf. A white dwarf is the corpse of a star. Sometime in the past, Sirius had a serious companion star. But it died leaving this shrunken husk of a sun behind. You need a very powerful telescope to see it.

One of the most colorful double star systems in the sky is located in the constellation of Cygnus. It’s called Alberio. It’s such a pretty pair, it’s often shown at star parties at observatories, planetariums, and museums. Truthfully, if the star system were a pretty girl, her poster would be in lockers and walls around the world

Alberio Circled

The star system is spectacular with the two blue and red stars shining brightly against the cosmic background. The good news here is you don’t need a large telescope to see them. A modest run of the mill telescope will split them nicely. Some people have even done it with good binoculars.