Carina - The Ship's Keel

Carina is a large constellation visible to southern hemisphere observers most of the year. This constellation is far to the south, and at mid-northern latitudes, it is only partially visible along the southern horizon. The Milky Way passes through Carina, which contains many bright open clusters and nebulae. In some ways, Carina is the Orion of the southern skies.

History and Mythology

Carina was once part of the ancient constellation Argo Navis, the Ship Argo, which carried Jason and his Argonauts on their quest for the Golden Fleece. Argo Navis is now divided into Carina, the Keel; Vela, the Sail; Puppis, the Stern; and Pyxis, the Ship's Compass.

Notable Stars

The brilliant star Canopus is located in Carina. It is the second brightest star in the sky, and it is visible from the southern parts of the United States directly south of Sirius. Canopus has a magnitude of -0.73. It is a white giant star lying at a distance of 310 light-years, and has a luminosity 15,000 times the Sun's. Canopus has been used by interplanetary spacecraft for navigation since it is very bright, and it lies far out of the ecliptic, the plane of Earth's orbit.

Beta Carinae, also called Miaplacidus, is the second-brightest star in Carina, at magnitude 1.7. It is a white subgiant star, about 111 light years away, with a luminosity of 210 Suns.

Second-magnitude Epsilon Carinae, the 3rd-brightest star in Carina, is too far south to have received a classical Greek or Arabic name. It was assigned the modern name Avior by the Royal Air Force in the 1930s, a name which has stuck. Avior is a spectroscopic binary system, with blue and orange giant components too close together to resolve visually, lying some 630 light years away.

Eta Carinae is a giant variable star surrounded by a bright orange cloud. This cloud is the result of a great outburst in the 1840s, which briefly made Eta Carinae the second-brightest star in the sky; today Eta is a modest star of 6th magnitude. Eta Carinae is a highly-unstable "hypergiant" star with as much as 100 times the Sun's mass, and will ultimately explode as a supernova.

Clusters, Nebulae, and Galaxies

Carina has several deep sky objects visible in small telescopes. Some of the star clusters and nebulae can be seen with the naked eye. The most prominent is the Eta Carinae nebula, or NGC 3372, in the region surrounding Eta Carinae. With binoculars one can see the nebula, which takes the form of three fan-shaped areas with dark lanes between them. The Keyhole Nebula is a famous dark zone seen at the center of the nebula, near Eta Carinae itself.

NGC 3199 is a bright nebula located in a region of scattered stars. There is dark material surrounding it, appearing to be a bay-shaped area on the northeast side of the nebula. NGC 3324 is another outlying part of the great Eta Carinae nebula complex.

The Gem Cluster, NGC 3293, is a small but very bright open cluster 1.6 degrees NW from the center of the Eta Carinae Nebula. It consists of more than 50 hot, young stars in a 6 arcminute field, lies at a distance of about 8400 light years, and is only about 6 million years old.

NGC 3532 is one of Carina's large open clusters, and it lies a few degrees west of the Keyhole Nebula. It is the brightest open cluster in this rich region, and contains about 120 stars.

NGC 2516 is a large open cluster visible with the naked eye. It is located on the edge of the Milky Way and contains about 100 stars. Under very clear skies, the 6th magnitude globular cluster NGC 2808 can be observed with binoculars. Using an 8 inch telescope, it resolves into hundreds of individual stars.

The prominent open cluster IC 2602 is often compared with the Pleiades and is commonly known as the "Southern Pleiades". It is also known as the Theta Carinae cluster.