Binary system

A binary system is an astronomical term referring to two objects in space (usually stars, but also planets, galaxies or asteroids) which are so close that their gravitational interaction causes them to orbit about a common center of mass. Some definitions (e.g. that of double planet, but not that of binary star) require that this center of mass is not located within the interior of either object. A multiple system is like a binary system but consists of three or more objects.

Binary companion (asteroids)

When binary asteroids are similar in size, they may be called "binary companions" instead of referring to the smaller body as a satellite. A good example of a true binary companion is the 90 Antiope system.

In popular culture

• Binary suns and star systems feature heavily in the Star Wars films and related material, the most notable example being the system in which the planet Tatooine is located.
• In the Discovery program Alien Planet, the planet Darwin IV orbits a binary system.
• In Star Trek, the planets Romulus and Remus are a binary system.
• In Spore, there are solar systems with two suns.
• In Escape To Witch Mountain and Return From Witch Mountain, Tony and Tia's home planet orbits 2 suns.
• "Futurama" has an episode with two suns.
• In the Invader Zim episode "Planet Jackers", one of the aforementioned Jackers mentions a binary system.

References

• Astronomy: A Visual Guide by Mark A. Garlick

See also

• Binary asteroid
• Binary star
• Contact binary
• Contact binary (asteroid)
• Double planet
• Rotational Brownian motion