3 Centauri

This article is about k Centauri. Not to be confused with K Centauri or κ Centauri.
3 Centauri
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Centaurus
Right ascension 13h 51m 49.60s[1]
Declination −32° 59′ 38.7″[1]
Apparent magnitude (V) 4.32[2] (4.52 + 5.97)[3]
Characteristics
Spectral type B5 III-IVp[4] + B8 V[5]
B−V color index −0.146±0.003[2]
Variable type Eclipsing?[6]
Astrometry
Radial velocity (Rv)+7.5±1.6[7] km/s
Absolute magnitude (MV)−0.46[2]
A
Proper motion (μ) RA: −34.698±0.864[8] mas/yr
Dec.: −27.909±0.792[8] mas/yr
Parallax (π)11.0982 ± 0.4267 mas
Distance290 ± 10 ly
(90 ± 3 pc)
B
Proper motion (μ) RA: −36.737±0.266[9] mas/yr
Dec.: −23.774±0.189[9] mas/yr
Parallax (π)10.2659 ± 0.1380 mas[9]
Distance318 ± 4 ly
(97 ± 1 pc)
Orbit[10]
PrimaryBa
CompanionBb
Period (P)17.428 d
Eccentricity (e)0.21
Periastron epoch (T)2443296.44 JD
Argument of periastron (ω)
(secondary)		15°
Semi-amplitude (K1)
(primary)		17 km/s
Details
3 Cen A
Mass5.0±0.1[11] M☉
Surface gravity (log g)3.80[12] cgs
Temperature17,500[12] K
Age47.4±7.3[11] Myr
3 Cen B
Mass2.47±0.10[5] M☉
Radius2.8[13] R☉
Luminosity50.2+11.7
−9.5[5] L☉
Temperature9,638+67
−66[5] K
Rotational velocity (v sin i)135[5] km/s
Other designations
k Centauri, 3 Cen, V983 Centauri, HIP 67669, WDS J13518-3300[14]
3 Cen A: GC 18724, HD 120709, HR 5210, SAO 204916
3 Cen B: GC 18725, HD 120710, HR 5211, SAO 204917
Database references
SIMBADdata
A
B

3 Centauri is a triple star[3] system in the southern constellation of Centaurus,[14] located approximately 300 light years from the Sun.[8][9] It is visible to the naked eye as a faint, blue-white hued star with a combined apparent visual magnitude of 4.32.[2] As of 2017, the two visible components had an angular separation of 7.851″ along a position angle of 106°.[3] The system has the Bayer designation k Centauri; 3 Centauri is the Flamsteed designation. It was a suspected eclipsing binary with a variable star designation V983 Centauri,[6] however the AAVSO website lists it as non-variable, formerly suspected to be variable.[15]

The brighter member, designated component A, is a magnitude 4.52[3] chemically peculiar star of the helium-weak (CP4) variety, and has a stellar classification of B5 III-IVp.[4] The spectrum of the star displays overabundances of elements such as nitrogen, phosphorus, manganese, iron, and nickel, while carbon, oxygen, magnesium, aluminium, sulfur, and chlorine appear underabundant relative to the Sun.[12] Weak emission line features are also visible.[16]

The magnitude 5.97[3] secondary, component B, is a single-lined spectroscopic binary star system with an orbital period of 17.4 days and an eccentricity of 0.21.[10] The pair have an angular separation of 2.485 mas. The visible component is a B-type main-sequence star with a class of B8 V.[5]

  1. ^ a b Cite error: The named reference van Leeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference Veramendi2014 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Sigut2000 was invoked but never defined (see the help page).
  5. ^ a b c d e f Cite error: The named reference zorec2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference dr2a was invoked but never defined (see the help page).
  9. ^ a b c d Cite error: The named reference dr2b was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Pourbaix2004 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  12. ^ a b c Cite error: The named reference Sadakane2018 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference PasinettiFracassini2001 was invoked but never defined (see the help page).
  14. ^ a b Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference AAVSO was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Wahlgren2004 was invoked but never defined (see the help page).