Star Facts: Canopus

Star Facts: Canopus
Canopus (Alpha Carinae) imaged using SLOOH's Chile 1 Wide Field [www.slooh.com]

Canopus (Alpha Carinae) located in the constellation Carina is a yellowish-white supergiant 313 light-years away, that is 65 times the size of our own Sun. At -0.72 magnitude, it is also the second brightest star in the night sky, second only to Sirius (-1.46), but lies so far south that it is invisible from latitudes north of 37 degrees, including most of Europe and the United States. From the Southern Hemisphere, however, both Sirius and Canopus can be seen high in the celestial heavens, like twin beacons illuminating the night sky.

Quick Facts

• Coordinates: RA 6h 23m 57.1s| Dec −52° 41′ 44.3810″
Star Type: Yellow-white Supergiant (F0Ib)
• Distance to Earth: 313 light years
• Constellation: Carina
• Apparent magnitude: -0.72
• Surface temp.: 7,350K
• Mass: 9.8 Solar masses
• Rotational Velocity: 8 km per second
• Radius: 30.88 million miles (71.4 solar radii)
• Luminosity: 15,100 times solar luminosity.

Location

Canopus is a southern constellation that lies 36 degrees below Sirius in Canis Major, and so cannot be seen north of +37 degrees latitude. For southern hemisphere observers, though, the night sky’s two brightest stars, Sirius and Canopus, often appear together high in the sky, where they shine like twin beacons.  Canopus has been used as a navigation pointer for spacecraft because its favorable angular separation from the Sun makes it an excellent star to regulate their altitude in orbit, in addition to the fact it is the most luminous star within 700 light-years of Earth.

Physical Properties

Canopus is yellowish-white giant star 65 times the size of our sun, and located 313 light-years away in the constellation Carina. It has a surface temperature of around 13,600 °F, compared to 10,000°F for the Sun, and shines more than 15,000 times brighter.

Scorpius-Centaurus Association

Canopus is a member of the Scorpius-Centaurus Association, which is the closest group of hot, massive OB class stars that share a common origin and proper motion. Other members of this association include Antares, and many other bright stars in the constellations of Scorpius, Centaurus, Crux, and Lupus.

Mythology

The Night Sky's 2nd Brightest Star: CanopusCanopus was pilot of the ship Argo Navis, that took King Menelaus to Troy in order to retrieve his wife Helen from the handsome young prince, Paris. Upon arrival, Canopus died after being bitten by a venomous snake the moment he stepped ashore, which prompted Menelaus to found a port on the spot, and name it in his honor. Some variations of the tale claim that Menelaus also conferred the name “Canopus” upon a very bright star that rose while he was delivering a speech in honor of the deceased pilot.

Many other cultures know, or have known of Canopus, and in almost all cases, the star features prominently in art, literature, religion, and science. Bedouin tribes , for instance, used Canopus and Polaris to navigate the featureless landscapes of the Negev and Sinai deserts, while in Botswana, Canopus is known as “Naka”, and its appearance in late winter announces the imminent arrival of the winds leading up to the start of the wet season. Canopus also appears on the flag of Brazil, where it represents Goiás state.