Definition of Alpha Centauri
: a binary star of magnitude zero that is the brightest star in the southern constellation Centaurus The plot centered on scientists John and Maureen Robinson and their three children, who in 1997 leave an overpopulated Earth to colonize a planet near Alpha Centauri.— Diane Tedeschi, Air & Space Smithsonian, August/September 1988
Note: What is visible in the night sky as the star Alpha Centauri is actually a binary system: two stars bound together gravitationally.
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