Zeta Centauri

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ζ Centauri
Observation data
Epoch J2000.0
Constellation
(pronunciation)
Centaurus
Right ascension 13h55m32.4s
Declination −47°17′18″
Apparent magnitude (V) 2.55
Characteristics
Spectral type B2.5IV
U-B color index −0.92
B-V color index −0.22
Variable type none
Astrometry
Radial velocity (Rv) +6.5 km/s
Proper motion (μ) RA: −57.14 mas/yr
Dec.: −44.75 mas/yr
Parallax (π) 8.48 ± 0.74 mas
Distance 385 ly (118 pc)
Absolute magnitude (MV) −2.81
Other designations
Alnair, HR 5231, HD 121263, SAO 224538, CD−46°8949, CP−46°6560, HIP 121263, GC 18809
Database references
SIMBAD data

Zeta Centauri (ζ Cen / ζ Centauri) is a star in the constellation Centaurus. It also has the traditional name Alnair or Al-Na'ir al Batn, from the Arabic البطن الناير Al-Na'ir al-baţn[u] meaning "The bright one of the stomach".

This is a spectroscopic binary star with a period of just over 8 days and an estimated orbital eccentricity of 0.5.

[edit] References

  • A. C. Maury, 1922, "The Orbit of the Spectroscopic Binary ζ Centauri", Harvard College Observatory Circular, vol. 233.