Triple star in the constellation Centaurus, the faintest component of which, Proxima Centauri, is currently the closest star to the Sun (about 4.2 light-years away). The two brighter components are about 0.2 light-year farther from the Sun. As seen from Earth, the system is the third brightest star (after Sirius and Canopus); Proxima is indistinguishable as a separate star to the unaided eye. Alpha Centauri can be seen from Earth's surface only from points south of about 40° N.
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Science: Starquakes Offer Clues to Alien Life ; Astronomers Have Been Listening in to the Seismic Upheavals Deep within the Core of Alpha Centauri, the Nearest Star to Us. and, Writes Ian Brown, It Sounds Remarkably like Our Own Sun
Aug 17, 2001; Every fan of science fiction and Trivial Pursuit will immediately name Alpha Centauri as our nearest star. It is not only the...