A binary star system is composed of two stars, which look very close to other starssphere systems ，Conjoint starIt means that two stars are orbiting around each otherQuality CenterOfStellar system。Double stars can be regarded as conjoined starssynonymIn general, however, binary stars can be conjoined or have no physical correlation, but they are together when viewed from EarthOptical binary。
The binary system isAstrophysicsIt is an important research topic in the study of the relationship between different celestial bodies.
In 1650, Giovanni Battista Riccioli（ursa major）Discover binary systems.
In 1685, in the southern skySouthern crossFather Fontenay found the brightCross IIDouble star system.
In 1767, John Mitchell first proposed that binary stars may be physically related to each other, and he thought that the possibility that binary stars are formed by aligning with each other is too small.
In 1779,William Herschel He began to observe the binary system, and soon published a catalog containing 700 pairs of binary stars.
In 1802, scientist William Herschel first put forward the term "double stars".
In 1827, the complete orbit of the first binary star system, Xi Ursa Major, was calculated by F é lix Savary.
In 1844, German astronomerBessel According to the wave pattern appearing in its moving path, it is inferred that Sirius is a binary star, because the star moves along a wavy track in nearby space.Sirius andcompanionAll inEccentricityThey orbit each other in quite large orbits with a period of 49.9 years and an average distance of aboutSun earth distance20 times.Although bright stars shine everywhere, useLarge telescopeIt is not difficult to see the companion star of Grade 7.Mass andsunlightIts radius is only 1/50 of the sun's, and its density is much larger than the sun's, with an average density of 30kg/cm3. It is the first one foundWhite dwarf。
On March 9, 2015, astronomers found that exoplanets orbit strange "four body" stars.[1]
binary star
Classification Introduction
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physical double
KonductraThere are many kinds.One star orbits anotherStellar motion, and have mutual gravitational action, called physical binary stars;Generally speaking, binary stars, unless otherwise specified, refer to physical binary stars.
Optical binary
The two stars seem to be very close, but the actual distance is very far, which is calledOptical binary。
Binary stars that can be identified only by analyzing spectral changes are calledSpectroscopic binary。
Eclipsing binary
When some binary stars revolve around each other, similar phenomena will occursolar eclipseSo that the brightness of such binary stars changes periodically.Such binary stars are calledEclipsing binaryOr eclipse variable stars.Eclipsing binaries are generally spectroscopic binaries.
Close binary
Other binaries are not only close to each other, but also have matter flowing from one child star to another. Such binaries are calledClose binary。
stayGalaxyThe number of binary stars is very large, estimated to be no less thanSingle star。Studying binary stars is not only for understandingStar formationAnd the diversity of evolution process is of great significance, and it is also an indispensable aspect for understanding the formation and evolution of the Milky Way.
Of oneUniversal gravitationIt is provided by another star, and vice versa.The ratio of their centripetal acceleration isinverse ratio。[2]
Note: the planet revolves around the star at a uniform speedCircular motionOr when the satellite moves around the planet in a circle, the distance of gravitational action is just the orbital radius of the planet (or satellite) in a circle, but the distance of gravitational action in a binary star system is different from the orbital radius of the binary star movementangular velocityIt must be the same as the period.TheirLinear velocityThe ratio is the same as the ratio of the track radius of their respective operation.
Formative theory
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Gravity formation theory
binary star
Although this possibility is quite low, it is not impossible to create a binary system by combining two stars through gravitational capture.In this process, three objects are needed, and according to the law of energy conservation, one object object is needed to take away the energy of the captured object.However, there are many binary systems, which cannot be the main procedure to form a binary system.
Disturbance formation theory
The positions of the three stars are close. Under the mutual disturbance of the three stars, the system will eventually throw out one of the three stars. It is assumed that without obvious further disturbance, the remaining two stars will form a stable binary system.
Mass transfer and accretion theory
When aMain sequence starIn the process of evolution, when the size increases, it may exceed itsRoche valve, which means that some matter may enter the region where the gravitational pull of the companion star is greater than its own gravity.The result is that the mass from a star overflows from the so-called Roche valveAccretion diskAbsorption or direct impact to another star（companion）, forming a double star system.
Orbital period
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StellarOrbital periodCan be less than an hour (e.gBeagleAM），Or several days (Beta Lyra), but there are also hundreds of thousands of years (aroundAlpha (Alpha Centauri AB)Adjacent star)。
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scientific research
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binary star
On August 28, 2012, an American astronomical research team released the latest research results“Kepler”Space telescopeIt is the first time to observe two planets orbiting a pair of stars in a binary star system.Previous astronomical studies have confirmed that most stars in the universe do not operate "alone" like the sun, but often accompany another star, and the two orbit each other.Astronomers have found planets orbiting these binary systems, but none of them has more than one.
According to the U.S. state that led the studyUniversity of San DiegoAstronomer Jerome Oros introduces the newly discoveredKonductraThe system is named "Kepler-47". One of the stars in this system has a volume similar to that of the sun, while the other has a volume only one-third of that of the sun.The size of the two planets isNeptuneClose, they revolve around a binary star in a fairly close orbit.
More importantly, the planet orbiting in the outermost orbit is located in what astronomers call the "habitable zone", and its further research may find that it is similar to the Earth'sHabitable planet。
A celestial body with two suns
binary star
On April 1, 2013, French scientists believed that they had been in a particularly remoteGalaxyIt captures the first celestial body 2MASS0103 (AB) b orbiting two sunsA picture, by FranceGrenobleJoseph Fourier University Philip Durham and his colleagues in November 2012.After consulting the archive data of the telescope, they found that this huge object had traveled a long distance between 2002 and 2012.
They believe that the orbital distance of the planetGeminiAbout 12.5 billion kilometers.It is far from itsPrimary starVery close, probably around the GeminiDust panMany planets were born in this way.However, the mass of 2MASS0103 (AB) b isJupiter12 to 14 times, located on planets and degraded starsBrown dwarfBetweenDividing lineOn.
ChileEuropean Southern ObservatoryThis image taken by our telescope shows a huge celestial body orbiting a pair of binary stars.However, its size is so large that researchers cannot determine whether it is a degraded star or a particularly large planet.They said that determining its identity would help people better understand how stars and planets are formed.
Planet with four suns
On October 17, 2011, British scientists confirmed a planet associated with four stars, which means that there are“Four suns”, which is the first time that this kind ofsphere systems 。This planet is locatedCygnus, about 3200 light-years away from the earth, about 6.2 times the size of the earth.
Researchers found that this planet, called PH1, revolves around a binary system, while another binary system revolves around the previous binary system, which means that four stars illuminate its sky at the same time.But such a system also puzzled astronomers, who did not understand how this planet could exist stably under the gravity of four stars without being "torn apart".
A binary system is a system in which two stars rotate around each other. This system is not rare, but there are not many binary systems with planets.Of the thousands of known planets, only six have been found to revolve around a binary system.The planet PH1 discovered this time is the first planet with another binary system.
