Kappa Centauri
Kappa Centauri (κ Cen, κ Centauri) is a binary star in the southern constellation of Centaurus. With an apparent visual magnitude of +3.14, it can be viewed with the naked eye on a dark night. Parallax measurements place it at an estimated distance of from Earth.

This is a spectroscopic binary system where the presence of an orbiting companion is revealed by shifts in the absorption lines caused by the Doppler effect. The primary component is a huge star, with about seven times the Sun's mass and four times the Sun's radius. It has a stellar classification of B2 IV, indicating that it is in the subgiant stage of its stellar evolution. An effective temperature of 19,800 K in the outer envelope is what gives it the blue-white hue of a B-type star.

The primary is a candidate Beta Cephei variable that shows line-profile variations in its spectrum. However, the nature of the variability remains uncertain because of the binary nature of the system. As of 2007, the secondary component was separated from the primary by 0.128 arcseconds at a position angle of 156°. It has about 68% of the mass of the primary. This system is a proper motion member of the Upper-Centaurus Lupus sub-group in the Scorpius-Centaurus OB association, the nearest such co-moving association of massive stars to the Sun.

In Chinese, (), meaning "Imperial Guards", refers to an asterism consisting of κ Centauri, γ Lupi, δ Lupi, β Lupi, λ Lupi, ε Lupi, μ Lup, π Lupi, ο Lupi and α Lupi. Consequently, the Chinese name for κ Centauri itself is (, .). From this Chinese name, the name Ke Kwan has appeared.
Q50053
binary star
Concept
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constellation
Concept
Q8844
Centaurus
CEL
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apparent visual magnitude
Concept
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Parallax
Concept
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Earth
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spectroscopic binary
Concept
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absorption line
Concept
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Doppler effect
Concept
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stellar classification
Concept
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subgiant
Concept
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stellar evolution
Concept
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effective temperature
Concept
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Beta Cephei variable
CEL
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spectrum
Concept
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arcsecond
Concept
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position angle
UNK
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proper motion
Concept
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Scorpius-Centaurus
CEL
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OB association
Concept
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Chinese
Concept
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Imperial Guards
CEL
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γ Lupi
CEL
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δ Lupi
CEL
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β Lupi
CEL
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λ Lupi
CEL
Q136713
ε Lupi
CEL
Q135568
μ Lup
CEL
Q136238
π Lupi
CEL
Q135564
ο Lupi
CEL
Q14230
α Lupi
CEL
Q7832287
Chinese name
UNK
Q2278229
Kappa Centauri
CEL
2007-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
2007
DATE
++3.14^^http://www.w3.org/2001/XMLSchema#decimal
+3.14
NUMBER
+2^^http://www.w3.org/2001/XMLSchema#decimal
2
NUMBER
+0.128^^http://www.w3.org/2001/XMLSchema#decimal
0.128
NUMBER
+68^^http://www.w3.org/2001/XMLSchema#decimal
68
NUMBER
constellation
type of variable star
instance of
instance of