Sigma Centauri

σ Centauri
Observation data
Epoch J2000.0      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 mas[1]
Distance412 ± 9 ly
(126 ± 3 pc)
Absolute magnitude (MV)−1.60[5]
Details
Mass6.8±0.1[3] M☉
Radius4.5[6] R☉
Luminosity1,101[7] L☉
Temperature15,744[7] K
Rotational velocity (v sin i)169[4] km/s
Age25.3±6.3[3] Myr
Other designations
σ Cen, CD−49° 7115, FK5 464, HD 108483, HIP 60823, HR 4743, SAO 223454.[8]
Database references
SIMBADdata

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]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference GutierrezMoreno1968 was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  4. ^ a b c d Cite error: The named reference Jilinski2006 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference PasinettiFracassini2001 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Rizzuto2013 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Gullikson2013 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Zboril1999 was invoked but never defined (see the help page).