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Alpha Centauri triple system

author: ESO/Novapix

reference: a-eto01-00110

Image Size 300 DPI: 32 * 22 cm

Location of the Alpha Centauri triple stellar system in the sky. The brighter stars (Alpha Centauri A and B) are strongly overexposed, with the outlying member, Proxima lying approx. 2.2° to the south-west (arrow). Smaller areas around the stars are shown in the inserts to the right. The photo has been reproduced from a blue-sensitive photographic plate obtained by the ESO 1-m Schmidt Telescope, a wide-angle telescope at the La Silla observatory in Chile that has now been decommissioned. The Alpha Centauri triple stellar system is our closest neighbour in space. It is located at a distance of 4.36 light-years, or 41 million million km, in the direction of the southern constellation Centaurus (The Centaur). The two main stars in the system, Alpha Centauri A and Alpha Centauri B, are rather similar to the Sun; their stellar spectral types are "G2V" and "K1V", respectively. The third star is a "red dwarf" known as Proxima. It is much cooler and smaller than the other two. Alpha Centauri A and B orbit each other at a distance of about 3600 million km, or somewhat more than the distance of planet Uranus from the Sun. The orbital period is almost exactly 80 years. Their smaller companion, Proxima, is about 1.5 million million km (10,000 Astronomical Units) nearer to the solar system than A and B. It is possibly orbiting that pair with a period of millions of years.

Keywords for this photo:

ALPHA CENTAURI - ASTRONOMY - BINARY STAR - BLACK AND WHITE - CENTAURUS - DWARF - FLARE STAR - K STAR - M STAR - PROXIMA CENTAURI - RED DWARF - SOUTHERN HEMISPHERE - STAR -