The Procyon System is located about 11.5 light-years (ly) from our Sun. Procyon A, or Alpha Canis Minoris A, is the brightest and most centrally located naked-eye star of Constellation Canis Minor (the Smaller Dog). Procyon is also the upper left member of the "Winter Triangle" of first magnitude stars, whose other components are Sirius (Alpha Canis Minoris) at lower left and Betelgeuse (Alpha Orionis) at right center.

In Star Trek, Procyon is most notable for the fact that in an alternate future, the Battle of Procyon V, fought in the 26th century over Procyon V, was the final battle in the invasion of the Sphere Builders. This was the battle in which the transdimensional aliens' encroachment into the Milky Way Galaxy was turned back by the forces of the Federation, including the USS Enterprise-J.(ENT: "Azati Prime")

In reality, Alpha Canis Minoris A has a close companion star B that is separated "on average" by only about 16 times the distance from the Earth to the Sun -- 14.9 astronomical units (AUs) of an orbital semi-major axis -- which is roughly the distance between Uranus and our Sun. Alpha Minoris B, the companion star, is a white dwarf, stellar remnant and is so dim that it cannot be perceived with the naked eye. After analyzing irregularities in the proper motion of Procyon which were first detected in 1840, Arthur Julius Georg Friedrich von Auswers (1838-1915) deduced the presence of this faint but massive companion and published a computed period of 40 years in 1861. However, Procyon B was not detected visually until 1896 by John M. Schaeberle (1853-1924) with the 36-inch refractor at Lick Observatory. There is a third optical companion C.

Procyon A , the Little Dog Star, is the eighth brightest star in the night sky as well as the brightest star in its constellation. Unlike Sol, it is a white-yellow main sequence dwarf star of spectral and luminosity type F5 V-IV . This relatively large star has about 1.5 times Sol's mass and about 1.4 to 2.3 times its diameter. Compared to Sol, moreover, Procyon A is hotter and about 7.5 times brighter. Procyon A is unusually bright for its spectral type and so may be becoming a subgiant star that is beginning to evolve off the main sequence, as it begins to fuse the increasing amounts of helium "ash" mixed with hydrogen at its core. Many astronomers believe that the star has entered the last phase of its life and is becoming dimmer.

The star is rich in elements heavier than hydrogen ("metals rich"), as it has about 1.4 times the iron abundance of Sol, and dust has been detected in the system (Kuchner and Brown, 2000 -- in postscript). It was probably enriched by its companion star, which was once bigger and hotter than Procyon A and so evolved and "burnt out" even faster. Procyon B manufactured lots of heavier elements which it puffed out into space and onto Procyon A before becoming a white dwarf.

The distance from Procyon A where an Earth-type planet would be "comfortable" with liquid water is centered around 2.7 AUs (about the middle of the main asteriod belt in the Solar System between Mars and Jupiter), where its orbit period would be 3.4 years long. If there is life on any Earth-type planet orbiting Procyon A, it is likely to be primitive single-cell bacteria under major bombardment by meteorites and comets as Earth was for the first few billion years. If oxygen-producing microbes have not yet had time to develop and generate free oxygen in the atmosphere of such a planet, it probably would not have an ozone layer (O3) although Procyon A puts out more ultraviolet radiation than Sol.