CARINA

In antiquity there was a large constellation called the Argo Navis recalling the myth of the great ship of Jason and the Argonauts which was part of the 48 constellations listed by Ptolemy. The constellation was divided into three parts in the 18th Century: Carina, Puppis and Vela. The second brightest star in the skies, Canopus, and deep-sky objects are found in the Carina constellation making it one of the most fascinating constellations in the celestial sphere.

The stars in the Carina constellation are the most southern in the Argo Navis and cannot be seen from Italy. The first sightings of these stars were those of Eratosthenes, best known for his calculations of the Earth’s circumference, who was in Egypt when he saw the star Canopus. In 1843 the star Eta had a sudden increase in its brightness which made it brighter than Canopus, almost reaching the magnitude of Sirius.

Canopus is the Alpha star, the brightest in the constellation and the second brightest in the skies after Sirius. It is a yellow supergiant 312 light-years from the Solar System. It is thought to be 20,000 times brighter than the Sun. Its name comes from the mythological Canopus who was the helmsman for Menelaus, King of Sparta, who was bitten by a serpent off the Egyptian coast, died and was transformed into a star.

Eta Carinae is one of the most interesting variable stars in the skies. It has undergone numerous increases in its luminosity and it is thought that it is nearing explosion in its evolutionary stage to become a supernova or a hyper-nova or even a hazardous Gamma Ray Burst. Studies show that we are dealing with a hyper-giant star, one of the biggest we know of. It has a companion and is 5 million times brighter than the Sun.