Gamma Centauri is a

binary star A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

system in the southern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Centaurus Centaurus () is a bright constellation in the southern sky. One of the 88 modern constellations by area, largest constellations, Centaurus was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one ...

, which is probably part of a wider system together with

Tau Centauri Tau Centauri, Latinized from τ Centauri, is a solitary star in the southern constellation of Centaurus. It is visible to the naked eye with an apparent visual magnitude of +3.86. The distance to this star, based upon an annual parallax s ...

. The system is visible to the naked eye as a single point of light with a combined

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light ca ...

of +2.17; individually they are third-magnitude stars.

Nomenclature

Its main name is a

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...

that is Latinized from γ Centauri, and abbreviated Gamma Cen or γ Cen. It has the proper name Muhlifain, not to be confused with Muliphein, which is

γ Canis Majoris Gamma Canis Majoris (γ Canis Majoris, abbreviated Gamma CMa, γ CMa), also named Muliphein , is a star in the constellation of Canis Major. It is unclear exactly why this relatively faint star was given the 'gamma' designation, but possi ...

; both names derive from the same Arabic root.

Characterstics

This system is located at a distance of about from the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

based on

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

. In 2000, the pair had an angular separation of 1.217

arcseconds A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a tu ...

with a

position angle In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the Celestial pole, north celestial pole (NCP), turning pos ...

of 351.9°. Their positions have been observed since 1897, which is long enough to estimate an

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

of 84.5 years and a

semimajor axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the long ...

of 0.93 arcsecond. At the distance of this system, this is equivalent to a physical separation of about . The stars have

spectral type In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...

s of A1IV and A0IV, suggesting they are A-type

subgiant A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution ...

stars in the process of becoming

giants A giant is a being of human appearance, sometimes of prodigious size and strength, common in folklore. Giant(s) or The Giant(s) may also refer to: Mythology and religion *Giants (Greek mythology) * Jötunn, a Germanic term often translated as 'g ...

. The stars have similar characteristics, with an estimated 2.8 times the

Sun's mass The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies a ...

, around 100 times the

Sun's luminosity The solar luminosity () is a unit of radiant flux ( power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal s ...

and an estimated

effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...

of 9,300 K. The star

very likely makes a widely-separated binary system with Gamma Centauri, it is a co-moving star with an estimated separation of . There is a 98% chance that they are gravitationally bound.

Etymology

Chinese astronomy Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The Ancient China, ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categori ...

, (), meaning ''

Arsenal An arsenal is a place where arms and ammunition are made, maintained and repaired, stored, or issued, in any combination, whether privately or publicly owned. Arsenal and armoury (British English) or armory (American English) are mostly ...

'', refers to an asterism consisting of γ Centauri, ζ Centauri, η Centauri,

θ Centauri Theta Centauri or θ Centauri, officially named Menkent (), is a single star in the southern constellation of Centaurus, the centaur. With an apparent visual magnitude of +2.06, it is the fourth-brightest member of the constellation. Ba ...

2 Centauri 2 Centauri is a single star in the southern constellation of Centaurus, located approximately 183 light-years from Earth. It has the Bayer designation g Centauri; ''2 Centauri'' is the Flamsteed designation. This object is visible to th ...

HD 117440 HD 117440, also known by its Bayer designation d Centauri, is a binary star system in the southern constellation of Centaurus. It is visible to the naked eye with a combined apparent visual magnitude of 3.90. The distance to this system ...

, ξ¹ Centauri,

τ Centauri Tau Centauri, Latinized from τ Centauri, is a solitary star in the southern constellation of Centaurus. It is visible to the naked eye with an apparent visual magnitude of +3.86. The distance to this star, based upon an annual parallax s ...

D Centauri D Centauri is a double star in the southern constellation of Centaurus. The system is faintly visible to the naked eye as a point of light with a combined apparent magnitude of +5.31; the two components are of magnitude 5.78 and 6.98, res ...

and

σ Centauri Sigma Centauri, Latinisation of names, Latinized from σ Centauri, is the Bayer designation for a solitary star in the southern constellation of Centaurus. It is visible to the naked eye with an apparent visual magnitude of 3.91. A visual c ...

. Consequently, the

Chinese name Chinese may refer to: * Something related to China * Chinese people, people identified with China, through nationality, citizenship, and/or ethnicity **Han Chinese, East Asian ethnic group native to China. **'' Zhonghua minzu'', the supra-ethni ...

for γ Centauri itself is (, ). The people of Aranda and

Luritja The Luritja or Loritja people, also known as Kukatja or Kukatja-Luritja, are an Aboriginal Australian people of the Northern Territory. Their traditional lands are immediately west of the Derwent River, that forms a frontier with the Arrernte p ...

tribe around

Hermannsburg Hermannsburg is a village and a former municipality in the Celle (district), Celle district, in Lower Saxony, Germany. Since 1 January 2015 it is part of the municipality Südheide (municipality), Südheide. It has been a state-recognised resort t ...

Central Australia Central Australia, also sometimes referred to as the Red Centre, is an inexactly defined region associated with the geographic centre of Australia. In its narrowest sense it describes a region that is limited to the town of Alice Springs and ...

named a quadrangular arrangement comprising this star, δ Cen (Ma Wei), δ Cru (Imai) and γ Cru (

Gacrux Gacrux is the third-brightest star in the southern constellation of Crux, the Southern Cross. It has the Bayer designation Gamma Crucis, which is Latinised from γ Crucis and abbreviated Gamma Cru or γ Cru. With an apparent visual magni ...

) as ''Iritjinga'' ("The Eagle-hawk").

Notes

References

{{DEFAULTSORT:Gamma Centauri A-type subgiants Binary stars Centaurus Centauri, Gamma BD-48 7597 110304 061932 4819 TIC objects