Astronomy:Sigma Centauri
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 12h 28m 02.38208s[1] |
| Declination | −50° 13′ 50.2872″[1] |
| Apparent magnitude (V) | 3.91[2] |
| Characteristics | |
| Spectral type | B3 V[3] |
| U−B color index | −0.805[2] |
| B−V color index | −0.202[2] |
| Astrometry | |
| Radial velocity (Rv) | +12.8±1.4[4] km/s |
| Proper motion (μ) | RA: −32.36[1] mas/yr Dec.: −12.51[1] mas/yr |
| Parallax (π) | 7.92 ± 0.18[1] mas |
| Distance | 412 ± 9 ly (126 ± 3 pc) |
| Absolute magnitude (MV) | −1.60[5] |
| Details | |
| Mass | 6.8±0.1[3] M☉ |
| Radius | 4.5[6] R☉ |
| Luminosity | 1,101[7] L☉ |
| Temperature | 15,744[7] K |
| Rotational velocity (v sin i) | 169[4] km/s |
| Age | 25.3±6.3[3] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Sigma Centauri, Latinized from σ Centauri, is the Bayer designation for a solitary[9] star in the southern constellation of Centaurus. It is visible to the naked eye with an apparent visual magnitude of 3.91.[2] A visual companion at an angular separation of 88.11±0.37 mas along a position angle of 14.33°±2.59° was detected in 2010 using interferometry,[10] but its association with Sigma Centauri remains undetermined as of 2013.[11] The distance to Sigma Centauri, based upon an annual parallax shift of 7.92 mas,[1] is around 412 light years.
This is a B-type main sequence star with a stellar classification of B3 V.[3] It is a helium-rich star, the most massive type of chemically peculiar star.[12] Sigma Centauri has around 6.8 times the mass of the Sun and 4.5[6] times the Sun's radius. It has a relatively high rate of spin with a projected rotational velocity of 169[4] km/s, and is around 25 million years old.[3] The star radiates 1,101 times the solar luminosity from its outer atmosphere at an effective temperature of 15,744[7] K. It is a member of the Lower Centaurus Crux component of the Scorpius–Centaurus association.[4]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (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.
- ↑ 3.0 3.1 3.2 3.3 3.4 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.
- ↑ 4.0 4.1 4.2 4.3 Jilinski, E. et al. (March 2006), "Radial velocity measurements of B stars in the Scorpius–Centaurus association", Astronomy and Astrophysics 448 (3): 1001–1006, doi:10.1051/0004-6361:20041614, Bibcode: 2006A&A...448.1001J.
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 6.0 6.1 Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367: 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P.
- ↑ 7.0 7.1 7.2 McDonald, I. et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–57, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M.
- ↑ "sig Cen". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=sig+Cen.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Rizzuto, A. C. et al. (December 2013), "Long-baseline interferometric multiplicity survey of the Sco-Cen OB association", Monthly Notices of the Royal Astronomical Society 436 (2): 1694–1707, doi:10.1093/mnras/stt1690, Bibcode: 2013MNRAS.436.1694R.
- ↑ Gullikson, Kevin; Dodson-Robinson, Sarah (January 2013), "Detection of Low-Mass-ratio Stellar Binary Systems", The Astronomical Journal 145 (1): 13, doi:10.1088/0004-6256/145/1/3, 3, Bibcode: 2013AJ....145....3G.
- ↑ Zboril, M.; North, P. (May 1999), "Properties of He-rich stars. II. CNO abundances and projected rotational velocities", Astronomy and Astrophysics 345: 244–248, Bibcode: 1999A&A...345..244Z.
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