prokyon

Prokyon, commonly known as Procyon in English, is the brightest star in the minor constellation Canis Minor. The name derives from the Greek Prokyon, meaning “before the dog,” in reference to its rising before the bright Dog Star, Sirius, in ancient times. In modern astronomy it is sometimes spelled with the same root as Procyon, while some languages use a variant such as Prokyón.

Prokyon A is an F-type star, classed as F5IV-V, meaning it is a yellow-white star that is somewhat evolved off the main sequence. It lies at a distance of about 11.4 light-years (roughly 3.5 parsecs) from the Sun, making it one of the nearer stars to Earth. Its apparent visual magnitude is about 0.34, placing it among the brighter stars visible from Earth. The star is part of a binary system.

The companion, Procyon B, is a white dwarf. The Procyon system has an orbital period of roughly 40 years, with the two components separated by a small angular distance that changes as they orbit. Procyon B is far fainter than Prokyon A, and it was first resolved as a separate component in the late 19th century.

Observationally, Prokyon is prominent in the northern skies during late winter and early spring evenings, located in Canis Minor near the more famous Sirius in Canis Major. The system is of interest in stellar astrophysics as a nearby example of an F-type star with a white dwarf companion, providing insights into binary evolution and end states of stars.