α Centauri System

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Alpha Centauri is a binary star comprising two Sun-like stars. It is also the nearest stellar system to the Sun at only 4.3 light years.

It is probably a triple system with the more distant third star, Proxima Cen, being loosely bound to the binary system.

R.A.: A: 14h 39m 36.4951s B: … 35.0803s
Dec.: A: -60° 50′ 02.308″ B: … 13.761″
parallax p = 0.75″
distance d = 1.34 parsecs = 4.37 light-yr
α Centauri is a double star (G2V + K1V)

Orbital elements:
Period P = 79.91 yr
Eccentricity e = 0.52
Semi-major axis a = 23.4 A.U.
Inclination i = 79°

Separation of stars 11.2 to 35.6 AU
Angular separation of stars varies 2 to 22″
2008: 8.3″
2009: 7.5″
2016: 4.0″
apastron: 1995, 2075
periastron: 1955, 2035

More data on alpha Centauri A, B and Proxima Centauri

Habitable zones of alpha Centauri A and B

Habitable zone planets

The habitable zone of a star is the zone where a planet can have liquid water.
For α Centauri A: habitable zone 1.1 – 1.3 AU (1″ from A)
For α Centauri B: habitable zone 0.5 – 0.9 AU (0.6″ from B)