Alpha Centauri b or Alpha Centauri B may refer to:
Stars Alpha Centauri B (Toliman), the second largest star in the α Cen trinary system
Planets Alpha Centauri Ab, an unconfirmed candidate exoplanet orbiting the largest star in the α Cen trinary star system, Rigel Kentarus (α Cen A) Alpha Centauri Bb, a disproven exoplanet orbiting the second largest star in the α Cen trinary star system, Toliman (α Cen B) Alpha Centauri Cb, an exoplanet orbiting the smallest star in the α Cen trinary star system, Proxima (α Cen C)
See also Alpha Centauri AB (binary star) Alpha Centauri (disambiguation) B Centauri (disambiguation) b Centauri b