Procyon

Procyon (α CMi, α Canis Minoris, Alpha Canis Minoris) is the brightest star in the constellation Canis Minor. To the naked eye, it appears to be a single star, the seventh brightest in the night sky with a visual apparent magnitude of 0.34. It is actually a binary star system, consisting of a white main-sequence star of spectral type F5 IV–V, named Procyon A, and a faint white dwarf companion of spectral type DA, named Procyon B. The reason for its brightness is not its intrinsic luminosity but its closeness to the Sun; as determined by the Hipparcos astrometry satellite, it lies at a distance of just 11.46 light-years (3.51 parsecs), and is therefore one of our nearest stellar neighbours. Its closest neighbour is Luyten's Star, about 1.12 ly (0.34 pc) away, and the latter would appear as a visual magnitude −7 star in the night sky of a hypothetical planet orbiting Procyon.