Astronomy:Kappa Centauri
  | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 14h 59m 09.68494s[1] |
| Declination | −42° 06′ 15.1069″[1] |
| Apparent magnitude (V) | +3.14[2] (3.34 + 4.71)[3] |
| Characteristics | |
| Spectral type | B2V + B3V[3] |
| U−B color index | −0.805[2] |
| B−V color index | −0.204[2] |
| Variable type | Candidate β Cep[4] |
| Astrometry | |
| Radial velocity (Rv) | +8.0[5] km/s |
| Proper motion (μ) | RA: −17.62[1] mas/yr Dec.: −22.51[1] mas/yr |
| Parallax (π) | 8.14 ± 0.33[3] mas |
| Distance | 400 ± 20 ly (123 ± 5 pc) |
| Absolute magnitude (MV) | –2.2[6] |
| Details | |
| κ Cen A | |
| Mass | 8.38±0.27[3] M☉ |
| Radius | 4.4±0.7[7] R☉ |
| Luminosity | 2,500[7] L☉ |
| Surface gravity (log g) | 4.02±0.20[7] cgs |
| Temperature | 20,900[3] K |
| Rotational velocity (v sin i) | 10[8] km/s |
| Age | 18.2±3.2[9] Myr |
| κ Cen B | |
| Mass | 4.41±0.36[3] M☉ |
| Temperature | 18,800[3] K |
| Orbit[3] | |
| Period (P) | 58.52±1.50 years |
| Semi-major axis (a) | 0.287″±0.008″ |
| Eccentricity (e) | 0.304±0.009 |
| Inclination (i) | 90.9±0.5° |
| Longitude of the node (Ω) | 156.1±0.5° |
| Periastron epoch (T) | 2011.10±0.30 |
| Argument of periastron (ω) (secondary) | 215.1±2.0° |
| Other designations | |
| Database references | |
| SIMBAD | data |
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 400 light-years (120 parsecs) 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]
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 20,900 K[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 18,800 K.[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, 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.[13] Consequently, the Chinese name for κ Centauri itself is 騎官三 (Qí Guān sān, English: the Third Star of Imperial Guards.).[14] From this Chinese name, the name Ke Kwan has appeared.[15]
See also
References
- ↑ 1.0 1.1 1.2 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V
- ↑ 2.0 2.1 2.2 2.3 Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A Photometric Investigation of the Scorpio-Centaurus Association", Astrophysical Journal Supplement 15: 459, doi:10.1086/190168, Bibcode: 1968ApJS...15..459G
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 3.13 Gómez, Jorge; Docobo, José A.; Campo, Pedro P.; Andrade, Manuel; Mendez, Rene A.; Costa, Edgardo (January 2022). "20 Orbits of binaries based on soar speckle observations" (in en). Monthly Notices of the Royal Astronomical Society 509 (3): 4229–4245. doi:10.1093/mnras/stab2633. ISSN 0035-8711. Bibcode: 2022MNRAS.509.4229G.
- ↑ 4.0 4.1 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, Timothy R.; Christensen-Dalsgaard, Jørgen, 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, 30, University of Toronto: International Astronomical Union, p. 57, Bibcode: 1967IAUS...30...57E
- ↑ 6.0 6.1 de Geus, E. J.; de Zeeuw, P. T.; 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
- ↑ 7.0 7.1 7.2 7.3 Hubrig, S. et al. (January 2009), "New magnetic field measurements of beta Cephei stars and Slowly Pulsating B stars", Astronomische Nachrichten 330 (4): 317, doi:10.1002/asna.200811187, Bibcode: 2009AN....330..317H
- ↑ 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, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T
- ↑ "kap Cen -- Variable Star", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Kappa+Centauri, retrieved 2012-01-23
- ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html.
- ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16
- ↑ (in 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, Script error: No such module "CS1 identifiers"..
- ↑ (in 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
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