Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. 3 Centauri is a binary star in the constellation Centaurus. It is approximately 298 light years from Earth. The primary component, 3 Centauri A, is a blue-white B-type giant with a mean apparent magnitude of +4.56. It is a variable star, and its brightness varies from magnitude +4.27 to +4.32 It is suspected the variations in luminosity are a result of the primary being an eclipsing binary, which would mean the system would consist of at least three objects. Its more distant companion, 3 Centauri B, is located 7.9 arcseconds away. It is a blue-white B-type main sequence dwarf and has an apparent magnitude of +6.06.