Constellation Chart

The Lesser Dog, The Little Dog

This small group of stars hugs the edge of the Milky Way. Among them lies Procyon, a near neighbour of the Sun lying just eleven light years away.

A tiny winter constellation of Canis Minor is found at opposite side of its mate of Canis Major separated by the Milky Way. Its only point of interest is in alpha CMi, Procyon. The star is one of members that forms the large asterism of the Winter's Great Triangle with Betelgeuse, alpha Ori, and Sirius, alpha Canis Majoris.

Procyon In Canis Minor

Procyon

PROCYON (Alpha Canis Minoris). The eastern anchor of the Winter Triangle, Procyon is the Alpha star of Canis Minor, the smaller dog. The Greek name means "before the dog," as in northern latitudes the star rises before Sirius, the "Dog Star," and its constellation, Canis Major, and announces their quick arrival. The eighth brightest star we see in the sky, Procyon is just behind Rigel in Orion. The star is bright in part, however, because it is close to us, a mere 11 1/4 light years away, compared with Rigel's 1600 light years. By comparison, Procyon is a feeble radiator even if it is still 7 times intrinsically more luminous than the Sun. The star is an example of a "subgiant," one that is just beginning its death process, its internal core hydrogen about all burned away to helium. Procyon's chief claim to fame is a tiny companion, Procyon B, a "white dwarf" discovered in 1895, though its existence was already known from the wobbles it exerts on the brighter star, Procyon A, which were discovered in 1844. Recent Hubble Space Telescope observations show that Procyon B has a temperature of 8700 degrees above absolute zero, a bit warmer than Procyon A's 6500 degree temperature, and is only about the size of Earth. Oddly, another member of the Winter Triangle, Sirius, has a similar companion. Both are dead stars that have gone through the entire cycle of stellar evolution and now consist of highly compressed gas that is just cooling off. At one time they were mighty stars brighter than their visible companions are today.

The name of Procyon means "Before the Dog", coming from the fact that this star rises just before (about 11 minutes at Tokyo) Sirius. The distance is estimated about 11.4 light years; Procyon is nearly as close to us as Sirius (8.7 light years away). Procyon had a former name of "Gomeisa", that means, "eye in tears". The star was regarded as being sad because many asterisms like Orion or bright stars in West Side of Milky Way left Gomeisa behind at the opposite side. Now, Gomeisa is named another principal star, beta CMi with third magnitude.

Canis Minor (the Smaller Dog) is a simple two-star figure seen here to the left of Gemini, which is easily recognizable by the twin stars Pollux and Castor at its top. (They are to the right of center near the edge; Pollux is the one on the left). The brightest star in the photograph, seen to the upper left of center, is Procyon of Canis Minor. Gomeisa, the Beta star in the constellation, is just down and to the right from Procyon. Procyon is at the northeast apex of the Winter Triangle.

Galaxy's In Canis Major

NGC 2350

NGC 2350 100X--very faint, small, elongated 2X1 in PA 110, very little brighter middle.

NGC 2538

NGC 2538 is a very faint, and small galaxy in Canis Minor.