Description
Described by Earth Sky as a "bright, giant star," figures on its mass and brilliance vary across sources. James Kaler, Professor Emeritus of Astronomy, University of Illinois calculates its brightness at a magnitude of -0.72 and its luminosity to be 13,300 times that of the Sun. He estimates its corona to be 10 times hotter. Earth Sky notes that Canopus is approaching the end of its life-cycle, owing to its great mass. Kaler suggests that it is currently experiencing dramatic shrinkage and surface heating, as it fuses its helium into carbon and oxygen. He raises the possibility that Canopus may evolve into a rare, neon-oxygen white dwarf, also known as a degenerate star.
Location
Despite its brilliance, Canopus cannot be viewed from any location above 37 degrees north of the equator, ruling out much of the northern hemisphere. Earth Sky notes that it can be observed in southern hemisphere night skies during the winter months. It calculates a distance from Earth of approximately 313 light years, compared to the estimate of 310 light years from Britannica. Mohawk Valley Astronomical Society states that Canopus can be seen from locations below the state of Virginia.
Mythology
Canopus is the brightest star within the ancient constellation of Argo Navis, the celestial ship of Jason and the Argonauts, which sailed in search of the Golden Fleece. The crew was protected by the goddess Athene, who subsequently immortalized the ship in the stars to commemorate their voyage. Canopus forms part of the keel, or rudder of the ship.
Navigation
Referred to as the "lighthouse of the universe," Canopus is an important navigational star, used by NASA to set coordinates. Britannica notes that its angular distance from the Sun makes it useful in altitude control for spacecrafts. It was used by the Syrian philosopher Poseidonius (130-50 BC) to estimate the size of the Earth.