Kappa Centauri

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Template:Short description

κ Centauri
Template:Location mark
Location of κ Centauri (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Centaurus
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) +3.14[2] (3.34 + 4.71)[3]
Characteristics
Spectral type B2V + B3V[3]
U−B Template:Engvar −0.805[2]
B−V Template:Engvar −0.204[2]
Variable type Candidate β Cep[4]
Astrometry
Radial velocity (Rv)+8.0[5] km/s
Proper motion (μ) RA: Script error: No such module "val". mas/yr[1]
Dec.: Script error: No such module "val". mas/yr[1]
Parallax (π)8.14±0.33 mas[3]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)–2.2[6]
Details
κ Cen A
MassScript error: No such module "val".[3] Template:Solar mass
RadiusScript error: No such module "val".[7] Template:Solar radius
Luminosity2,500[7] Template:Solar luminosity
Surface gravity (log g)Script error: No such module "val".[7] cgs
Temperature20,900[3] K
Rotational velocity (v sin i)10[8] km/s
AgeScript error: No such module "val".[9] Myr
κ Cen B
MassScript error: No such module "val".[3] Template:Solar mass
Temperature18,800[3] K
Metallicity [Fe/H]{{{metal_fe2}}} dex
Orbit[3]
Period (P)Script error: No such module "val". years
Semi-major axis (a)Script error: No such module "val".
Eccentricity (e)Script error: No such module "val".
Inclination (i)Script error: No such module "val".°
Longitude of the node (Ω)Script error: No such module "val".°
Periastron epoch (T)Script error: No such module "val".
Argument of periastron (ω)
(secondary)
Script error: No such module "val".°
Other designations
CD−41°9342,FK5 553, HD 132200, HIP 73334, HR 5576, SAO 225344.[10]
Database references
SIMBADdata

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Kappa Centauri (κ Cen, κ Centauri) is a binary star in the southern constellation of Centaurus. With an apparent visual magnitude of +3.14,[2] it can be viewed with the naked eye on a dark night. Parallax measurements place it at an estimated distance of Script error: No such module "convert". from Earth.[3]

Characteristics

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. They take 58 years to complete an orbit, have a small eccentricity of 0.304, and are seen orbiting nearly edge-on.[3]

File:KapCenLightCurve.png
A light curve for Kappa Centauri, plotted from TESS data.[11]

The primary component has about 8.4 times the Sun's mass[3] and four times the Sun's radius.[7] It has a stellar classification of B2V,[3] indicating that it is in the main sequence stage of its stellar evolution. An effective temperature of Script error: No such module "val".[3] in the outer envelope is what gives it the blue-white hue of a B-type star.[12] It 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.[4]

The secondary is also a B-type main-sequence star, of spectral class B3V. It has 4.4 times the Sun's mass and an effective temperature of Script error: No such module "val"..[3]

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.[6]

In Chinese astronomy

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), 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.[13] Consequently, the Chinese name for κ Centauri itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx.).[14] From this Chinese name, the name Ke Kwan has appeared.[15]

See also

References

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  13. Template:In lang 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Template:ISBN.
  14. Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 25 日 Template:Webarchive
  15. Richard Hinckley Allen: Star Names — Their Lore and Meaning: Centaurus

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Template:Stars of Centaurus