Glossary of Astronomical Terms/Alpha Centauri

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Alpha Centauri is the closest star system to Earth (4.3 light years). In the southern hemisphere, it can be viewed as one of the brightest objects outside of our solar system.

Alpha Centauri is actually a triple star system, consisting of Alpha Centauri A and Alpha Centauri B (which together form a binary star, and Proxima Centauri, a red dwarf. It is possible that Proxima Centauri is in orbit around the A and B stars. Of the three stars, Proxima is the one closest to Earth, and so it is the closest star to us after the Sun.

Computer models suggest that the A and B stars are excellent candidates for having Earth-like (terrestrial) planets, but probably not gas-giant planets like Saturn and Jupiter. In our own solar system, Saturn and Jupiter may have played a crucial role in obtaining our water supply by drawing comets towards the center of the solar system, so the question arises whether or not any terrestrial planets which might exist in the Alpha Centauri system have water.

Illustration courtesy of Wikipedia.