Gamma Centauri

Gamma Centauri

Template:Location mark Location of γ Centauri (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Centaurus
Right ascension	Template:RA
Declination	Template:DEC
Apparent magnitude (V)	+2.17 (+2.85/+2.95)
Characteristics
Spectral type	A1IV+ (A1IV + A0IV)
U−B Template:Engvar	−0.01
B−V Template:Engvar	−0.01
Astrometry
Radial velocity (Rv)	−5.5 km/s
Proper motion (μ)	RA: −185.72 mas/yr Dec.: +5.79 mas/yr
Parallax (π)	25.06±0.28 mas
Distance	Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)	−0.81
Orbit
Companion	γ Centauri B
Period (P)	yr
Semi-major axis (a)	″
Eccentricity (e)
Inclination (i)	°
Longitude of the node (Ω)	°
Periastron epoch (T)	1931.25 ± 0.07
Argument of periastron (ω) (secondary)	°
Details
Mass	2.8 Template:Solar mass
Radius	Template:Solar radius calculatorTemplate:Efn Template:Solar radius
Luminosity	95 Template:Solar luminosity
Surface gravity (log g)	3.52 cgs
Temperature	9,300 K
Metallicity	−0.29
B
Mass	2.8 Template:Solar mass
Radius	Template:Solar radius calculatorTemplate:Efn Template:Solar radius
Luminosity	95 Template:Solar luminosity
Temperature	9,300 K
Metallicity [Fe/H]	{{{metal_fe2}}} dex
Other designations
Template:Odlist
Database references
SIMBAD	data

Gamma Centauri is a binary star system in the southern constellation of Centaurus, which is probably part of a wider system together with Tau Centauri. The system is visible to the naked eye as a single point of light with a combined apparent visual magnitude of +2.17; individually they are third-magnitude stars.

Nomenclature

Its main name is a Bayer designation 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; both names derive from the same Arabic root.

Characteristics

This system is located at a distance of about from the Sun based on parallax. In 2000, the pair had an angular separation of 1.217 arcseconds with a position angle of 351.9°. Their positions have been observed since 1897, which is long enough to estimate an orbital period of 84.5 years and a semimajor axis of 0.93 arcsecond. At the distance of this system, this is equivalent to a physical separation of about .

The stars have spectral types of A1IV and A0IV, suggesting they are A-type subgiant stars in the process of becoming giants. The stars have similar characteristics, with an estimated 2.8 times the Sun's mass, around 100 times the Sun's luminosity and an estimated effective temperature of 9,300 K.

The star Tau Centauri 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

In Chinese astronomy, (), meaning Arsenal, refers to an asterism consisting of γ Centauri, ζ Centauri, η Centauri, θ Centauri, 2 Centauri, HD 117440, ξ¹ Centauri, τ Centauri, D Centauri and σ Centauri. Consequently, the Chinese name for γ Centauri itself is (, Template:Langx).

The people of Aranda and Luritja tribe around Hermannsburg, Central Australia named a quadrangular arrangement comprising this star, δ Cen (Ma Wei), δ Cru (Imai) and γ Cru (Gacrux) as Iritjinga ("The Eagle-hawk").