Binary system (astronomy)

"Binary system" redirects here. For other uses, see Binary system (disambiguation).

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 (minor planets)

When binary minor planets are similar in size, they may be called "binary companions" instead of referring to the smaller body as a satellite. Good examples of true binary companions are the 90 Antiope and the 79360 Sila–Nunam systems.

In popular culture

• Binary suns and star systems are featured 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 The Hitchhiker's Guide to the Galaxy, the planet Magrathea orbits a binary system
• In Spore, there are planetary 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 three suns.
• In the Invader Zim episode "Planet Jackers", one of the aforementioned Jackers mentions a binary system.
• In Star Trek Voyager, there is a system with two suns.
• In Doctor Who, Gallifrey (the home planet of the Time Lords) has two suns in its planetary system.
• Binary sun systems are featured in the Mass Effect 2 game, these systems are in the Milky Way as explorable areas.

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