Binary system (astronomy)
Encyclopedia
A binary system is an astronomical
term referring to two objects in space (usually star
s, but also planet
s, galaxies
or asteroid
s) 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.
" instead of referring to the smaller body as a satellite. A good example of a true binary companion is the 90 Antiope
system.
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
term referring to two objects in space (usually star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s, but also planet
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
s, galaxies
Galaxy
A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...
or asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
s) which are so close that their gravitational interaction causes them to orbit about a common center of mass
Center of mass
In physics, the center of mass or barycenter of a system is the average location of all of its mass. In the case of a rigid body, the position of the center of mass is fixed in relation to the body...
. Some definitions (e.g. that of double planet
Double planet
In astronomy, double planet and binary planet are informal terms used to describe a binary system of two astronomical objects that each satisfy the definition of planet and that are near enough to each other to have a significant gravitational effect on each other compared with the effect of the...
, but not that of binary star
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
) 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 companionsBinary asteroid
A binary asteroid is a system of two asteroids orbiting their common center of mass, in analogy with binary stars. 243 Ida was the first binary asteroid to be identified when the Galileo spacecraft did a flyby in 1993...
" instead of referring to the smaller body as a satellite. A good example of a true binary companion is the 90 Antiope
90 Antiope
The most remarkable feature of Antiope is that it consists of two components of almost equal size , making it a truly "double" asteroid. Its binary nature was discovered on 10 August 2000 by a group of astronomers using adaptive optics at the Keck Telescope on Mauna Kea. The "secondary" is...
system.
In popular culture
- Binary suns and star systems are featured heavily in the Star WarsStar WarsStar Wars is an American epic space opera film series created by George Lucas. The first film in the series was originally released on May 25, 1977, under the title Star Wars, by 20th Century Fox, and became a worldwide pop culture phenomenon, followed by two sequels, released at three-year...
films and related material, the most notable example being the system in which the planet TatooineTatooineTatooine is a fictional planet and setting for many key scenes in the Star Wars saga, appearing in every Star Wars film except The Empire Strikes Back, although it is mentioned at the end of the movie...
is located. - In the Discovery program Alien PlanetAlien PlanetAlien Planet is a 94-minute docufiction, originally airing on the Discovery Channel, about two internationally built robot probes searching for alien life on the fictional planet Darwin IV. It was based on the book Expedition, by sci-fi/fantasy artist and writer Wayne Douglas Barlowe, who was also...
, the planet Darwin IVDarwin IVDarwin IV is a fictional planet that was the subject of Wayne Barlowe's book Expedition and the television special, Alien Planet, based on Expedition...
orbits a binary system. - In Star TrekStar TrekStar Trek is an American science fiction entertainment franchise created by Gene Roddenberry. The core of Star Trek is its six television series: The Original Series, The Animated Series, The Next Generation, Deep Space Nine, Voyager, and Enterprise...
, the planets Romulus and Remus are a binary system. - In The Hitchhiker's Guide to the Galaxy, the planet Magrathea orbits a binary system
- In SporeSpore (2008 video game)Spore is a multi-genre single-player god game developed by Maxis and designed by Will Wright. The game was released for the Microsoft Windows and Macintosh operating systems in September 2008 as Spore...
, there are solar systems with two suns. - In Escape To Witch MountainEscape to Witch MountainEscape to Witch Mountain is a science fiction novel written by Alexander Key in 1968. It was adapted into a film of the same name by Walt Disney Productions in 1975, directed by John Hough. A remake directed by Peter Rader was released in 1995...
and Return From Witch MountainReturn from Witch MountainReturn from Witch Mountain is the 1978 sequel to Walt Disney Productions' 1975 film, Escape to Witch Mountain. It was written by Malcolm Marmorstein and is based on the novel by Alexander Key. Ike Eisenmann, Kim Richards, and Denver Pyle reprise their roles as Tony, Tia, and Uncle Bené—humanoid...
, Tony and Tia's home planet orbits 2 suns. - "FuturamaFuturamaFuturama is an American animated science fiction sitcom created by Matt Groening and developed by Groening and David X. Cohen for the Fox Broadcasting Company. The series follows the adventures of a late 20th-century New York City pizza delivery boy, Philip J...
" has an episode with three suns. - In the Invader ZimInvader ZimInvader Zim is an American animated television series created by Jhonen Vasquez. It was produced by and subsequently aired on Nickelodeon. The series revolves around an extraterrestrial named Zim from the planet Irk, and his ongoing mission to conquer and destroy Earth...
episode "Planet Jackers", one of the aforementioned Jackers mentions a binary system. - In Star TrekStar TrekStar Trek is an American science fiction entertainment franchise created by Gene Roddenberry. The core of Star Trek is its six television series: The Original Series, The Animated Series, The Next Generation, Deep Space Nine, Voyager, and Enterprise...
Voyager, there is a system with two suns. - In Doctor WhoDoctor WhoDoctor Who is a British science fiction television programme produced by the BBC. The programme depicts the adventures of a time-travelling humanoid alien known as the Doctor who explores the universe in a sentient time machine called the TARDIS that flies through time and space, whose exterior...
, GallifreyGallifreyGallifrey is a fictional planet in the long-running British science fiction television series Doctor Who and is the homeworld of the Doctor and the Time Lords...
(the home planet of the Time Lords) has two suns in its solar systemSolar SystemThe Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
.
See also
- Binary asteroidBinary asteroidA binary asteroid is a system of two asteroids orbiting their common center of mass, in analogy with binary stars. 243 Ida was the first binary asteroid to be identified when the Galileo spacecraft did a flyby in 1993...
- Binary starBinary starA binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
- Contact binaryContact binaryIn astronomy, a contact binary is a binary star system whose component stars are so close that they touch each other or have merged to share their gaseous envelopes. A binary system whose stars share an envelope may also be called an overcontact binary...
- Contact binary (asteroid)Contact binary (asteroid)In the study of asteroids, a contact binary is caused when two asteroids gravitate toward each other until they touch, forming an oddly-shaped single body. Asteroids suspected of being contact binaries include the unusually elongated 624 Hektor and the bilobated 216 Kleopatra and 4769 Castalia...
- Double planetDouble planetIn astronomy, double planet and binary planet are informal terms used to describe a binary system of two astronomical objects that each satisfy the definition of planet and that are near enough to each other to have a significant gravitational effect on each other compared with the effect of the...
- Rotational Brownian motionRotational Brownian motion (astronomy)In astronomy, rotational Brownian motion refers to the random walk in orientation of a binary star's orbital plane, induced by gravitational perturbations from passing stars.-Theory:...