Sigma Centauri

σ Centauri
Observation data; Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Centaurus
Right ascension	12h 28m 02.38208s
Declination	−50° 13′ 50.2872″
Apparent magnitude (V)	3.91
Characteristics
Spectral type	B3 V
U−B color index	−0.805
B−V color index	−0.202
Astrometry
Radial velocity (Rv)	+12.8±1.4 km/s
Proper motion (μ)	RA: −32.36 mas/yr ; Dec.: −12.51 mas/yr
Parallax (π)	7.92±0.18 mas
Distance	412 ± 9 ly ; (126 ± 3 pc)
Absolute magnitude (MV)	−1.60
Details
Mass	6.8±0.1 M☉
Radius	4.5 R☉
Luminosity	1,101 L☉
Temperature	15,744 K
Rotational velocity (v sin i)	169 km/s
Age	25.3±6.3 Myr
Other designations
	σ Cen, CD−49°7115, FK5 464, HD 108483, HIP 60823, HR 4743, SAO 223454.
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 times the Sun's radius.^[6] It has a relatively high rate of spin with a projected rotational velocity of 169 km/s,^[4] 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 K.^[7] It is a member of the Lower Centaurus Crux component of the Scorpius–Centaurus association.^[4]

References

^ ^a ^b ^c ^d ^e ^f van Leeuwen, F. (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, S2CID 18759600.
^ ^a ^b ^c ^d 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.
^ ^a ^b ^c ^d ^e 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, S2CID 118629873.
^ ^a ^b ^c ^d Jilinski, E.; et al. (March 2006), "Radial velocity measurements of B stars in the Scorpius–Centaurus association", Astronomy and Astrophysics, 448 (3): 1001–1006, arXiv:astro-ph/0601643, Bibcode:2006A&A...448.1001J, doi:10.1051/0004-6361:20041614, S2CID 17818058.
^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
^ ^a ^b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (3rd ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
^ ^a ^b ^c McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
^ "sig Cen". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-01-12.
^ 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
^ 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, arXiv:1309.3811, Bibcode:2013MNRAS.436.1694R, doi:10.1093/mnras/stt1690.
^ Gullikson, Kevin; Dodson-Robinson, Sarah (January 2013), "Detection of Low-Mass-ratio Stellar Binary Systems", The Astronomical Journal, 145 (1): 13, arXiv:1210.6360, Bibcode:2013AJ....145....3G, doi:10.1088/0004-6256/145/1/3, S2CID 118517725, 3.
^ 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.

[vanLeeuwen2007-1] ^ ^a ^b ^c ^d ^e ^f van Leeuwen, F. (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, S2CID 18759600.

[GutierrezMoreno1968-2] 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.

[Tetzlaff2011-3] 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, S2CID 118629873.

[Jilinski2006-4] Jilinski, E.; et al. (March 2006), "Radial velocity measurements of B stars in the Scorpius–Centaurus association", Astronomy and Astrophysics, 448 (3): 1001–1006, arXiv:astro-ph/0601643, Bibcode:2006A&A...448.1001J, doi:10.1051/0004-6361:20041614, S2CID 17818058.

[Anderson2012-5] Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.

[PasinettiFracassini2001-6] Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (3rd ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.

[Mcdonald2012-7] McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.

[SIMBAD-8] "sig Cen". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-01-12.

[Eggleton2008-9] 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.

[Rizzuto2013-10] 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, arXiv:1309.3811, Bibcode:2013MNRAS.436.1694R, doi:10.1093/mnras/stt1690.

[Gullikson2013-11] Gullikson, Kevin; Dodson-Robinson, Sarah (January 2013), "Detection of Low-Mass-ratio Stellar Binary Systems", The Astronomical Journal, 145 (1): 13, arXiv:1210.6360, Bibcode:2013AJ....145....3G, doi:10.1088/0004-6256/145/1/3, S2CID 118517725, 3.

[Zboril1999-12] 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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Sigma Centauri

References

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