Epoch J2000.0 Equinox J2000.0
|Right ascension||14h 59m 09.68494s|
|Declination||−42° 06′ 15.1069″|
|Apparent magnitude (V)||+3.14|
|Spectral type||B2 IV|
|U−B color index||−0.805|
|B−V color index||−0.204|
|Variable type||Candidate β Cep|
|Radial velocity (Rv)||+8.0 km/s|
|Proper motion (μ)||RA: −17.62 mas/yr
Dec.: −22.51 mas/yr
|Parallax (π)||8.51 ± 0.54 mas|
|Distance||380 ± 20 ly
(118 ± 7 pc)
|Absolute magnitude (MV)||–2.2|
|κ Cen A|
|Mass||7.2 ± 0.5 M☉|
|Radius||4.4 ± 0.7 R☉|
|Surface gravity (log g)||4.02 ± 0.20|
|Temperature||19,800 ± 900 K|
|Rotational velocity (v sin i)||10 km/s|
|Age||18.2 ± 3.2 Myr|
|κ Cen B|
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 380 light-years (120 parsecs) 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, 騎官 (Qí Guān), 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, κ Centauri itself is known as 騎官三 (Qí Guān sān, English: the Third Star of Imperial Guards.). From this Chinese name, the name Ke Kwan was appeared.
See also 
- van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357
- Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A Photometric Investigation of the Scorpio-Centaurus Association", Astrophysical Journal Supplement 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168
- Hubrig, S. et al. (January 2009), "New magnetic field measurements of beta Cephei stars and Slowly Pulsating B stars", Astronomische Nachrichten 330 (4): 317, arXiv:0902.1314, Bibcode:2009AN....330..317H, doi:10.1002/asna.200811187
- Schrijvers, C.; Telting, J. H.; De Ridder, J. (2002), "A Spectroscopic Search for Non-Radial Pulsations in Early B-Type Stars", in Aerts, Conny; Bedding, Jørgen; Christensen-Dalsgaard, Radial and Nonradial Pulsations as Probes of Stellar Physics, ASP Conference Proceedings 259, San Francisco: Astronomical Society of the Pacific, p. 204, Bibcode:2002ASPC..259..204S
- Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E
- de Geus, P. T.; de Zeeuw; Lub, J. (June 1989), "Physical parameters of stars in the Scorpio-Centaurus OB association", Astronomy and Astrophysics 216 (1-2): 44–61, Bibcode:1989A&A...216...44D
- Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago 239 (1). Bibcode:1970CoAsi.239....1B.
- Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (january 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x
- Kouwenhoven, M. B. N. et al. (October 2007), "The primordial binary population. II. Recovering the binary population for intermediate mass stars in Scorpius OB2", Astronomy and Astrophysics 474 (1): 77–104, arXiv:0707.2746, Bibcode:2007A&A...474...77K, doi:10.1051/0004-6361:20077719
- "kap Cen -- Variable Star", SIMBAD (Centre de Données astronomiques de Strasbourg), retrieved 2012-01-23
- "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16
- (Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 25 日
- Richard Hinckley Allen: Star Names — Their Lore and Meaning: Centaurus