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Alpha Centauri

The third brightest star in the sky is a system made of 3 stars: Alpha Centauri A, B and the star next to us, Proxima Centauri.
The sunlike Alpha Centauri A and the orange B could have planets. Proxima is a red dwarf and a flare star, which from time to time shows intense bursts.

Constellation: Centaurus
Age: 6 billion years
Distance of A and B: 4.395 light-years
Space between Alpha Centauri A and B: 24 AU
Orbit period of Alpha Centauri A and B: 79.92 years
Space between Proxima Centauri and A/B: 17 652 AU
Orbit period of Proxima Centauri around A and B: 500 000 years

Alpha Centauri A

Spectral class: G2
Visual magnitude: 0.01
Luminosity: 1.567 * Sun
Mass: 1.1 * Sun
Diameter: 1.227 * Sun
Radial velocity: -26.2 km/sec

Alpha Centauri B

Spectral class: K4
Visual magnitude: 1.34
Luminosity: 0.460 * Sun
Mass: 0.85 * Sun
Diameter: 0.865 * Sun
Radial velocity: -18.1 km/sec

Proxima Centauri

Spectral class: M5e
Visual magnitude: 11.05
Luminosity: 0.0000555 * Sun
Mass: 0.123 * Sun
Diameter: 0.145 * Sun
Radial velocity: -16 km/sec
Distance: 4.223 light-years

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    Alpha Centauri
The bright spot consists of the components A and B (inserted as photomontage), the arrow marks Proxima Centauri.
Photo: ESO

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