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'''Canopus''', also known as '''Alpha Carinae''', is the brightest star in the constellation of [[Carina]].  It is also the second brightest star in the night sky, with only [[Sirius]] appearing more luminous.  The [[star]] has an apparent magnitude of -0.72, making it easily visible in even heavily light polluted skies.

'''Canopus''', also known as '''Alpha Carinae''', is the brightest star in the constellation of [[Carina]].  It is also the second brightest star in the night sky, with only [[Sirius]] appearing more luminous.  The [[star]] has an apparent magnitude of -0.72, making it easily visible in even heavily light polluted skies.

Because Canopus is 53 degrees south of the [[celestial equator]], it is not visible in latitudes above 37 degrees north, which exclude most of [[Europe]], all of [[Canada]], and half the continental [[United States]].  The star itself is a rare example of a F class [[supergiant]].<ref name="simbad">http://simbad.u-strasbg.fr/simbad/sim-id?Ident=name+canopus</ref>

Because Canopus is 53 degrees south of the [[celestial equator]], it is not visible in latitudes above 37 degrees north, which includes most of [[Europe]], all of [[Canada]], and half the continental [[United States]].  The star itself is a rare example of a F class [[supergiant]].<ref name="simbad">http://simbad.u-strasbg.fr/simbad/sim-id?Ident=name+canopus</ref>

==Canopus in History==

==Canopus in History==

The name Canopus itself is a [[Latin]] derivative of the [[Greek]] name ''Kanôbos'', first recorded in [[Ptolemy|Ptolemy's]] famous [[Almagest]], or "Great Book".<ref name="allen">Allen, Richard Hinckley (1963). Star Names: Their Lore and Meaning (Revised ed.). New York: Dover Publications. pp. 67–72. ISBN 0486210790.</ref>  The exact origin of the name though is lost in time, although there are a couple hypotheses to its origin:

The name Canopus itself is a [[Latin]] derivative of the [[Greek]] name ''Kanôbos'', first recorded in [[Ptolemy|Ptolemy's]] famous [[Almagest]], or "Great Book".<ref name="allen">Allen, Richard Hinckley (1963). Star Names: Their Lore and Meaning (Revised ed.). New York: Dover Publications. pp. 67–72. ISBN 0486210790.</ref>  The exact origin of the name though is lost in time, although there are a couple hypotheses to its origin:

:*Canopus was once the brightest star of the ancient constellation of Argo, the ship Jason and the Argonauts used to search for the Golden Fleece in [[Greek mythology]].  The star itself named after another ship's pilot.

:*Canopus was once the brightest star of the ancient constellation of Argo, the ship Jason and the Argonauts used to search for the Golden Fleece in [[Greek mythology]].  The star itself was named after another ship's pilot.

:*From the [[Egyptian]] [[Copic]] name ''Kahi Nub'', meaning "Golden Earth", possibly because the star appeared more yellowish, thanjs to the reddening effect by the [[atmosphere]] on the star's light at its position near the horizon.<ref name="allen">Allen, Richard Hinckley (1963). Star Names: Their Lore and Meaning (Revised ed.). New York: Dover Publications. pp. 67–72. ISBN 0486210790.</ref>

:*From the [[Egyptian]] [[Copic]] name ''Kahi Nub'', meaning "Golden Earth", possibly because the star appeared more yellowish, thanks to the reddening effect by the [[atmosphere]] on the star's light at its position near the horizon.<ref name="allen">Allen, Richard Hinckley (1963). Star Names: Their Lore and Meaning (Revised ed.). New York: Dover Publications. pp. 67–72. ISBN 0486210790.</ref>

Other names for the star include '''Suhali''', occasionally used in English, based off of the Arabic name for various bright stars , سهيل ''suhayl''.  The [[Chinese]] referred to the star as 老人星 or ''Lǎorénxīng'', meaning "Star of the Old".  In Ancient [[India]], it was known as '''Agasti''' or '''Agastya'''. <ref name="allen">Allen, Richard Hinckley (1963). Star Names: Their Lore and Meaning (Revised ed.). New York: Dover Publications. pp. 67–72. ISBN 0486210790.</ref>

Other names for the star include '''Suhali''', occasionally used in English, based off of the Arabic name for various bright stars , سهيل ''suhayl''.  The [[Chinese]] referred to the star as 老人星 or ''Lǎorénxīng'', meaning "Star of the Old".  In Ancient [[India]], it was known as '''Agasti''' or '''Agastya'''. <ref name="allen">Allen, Richard Hinckley (1963). Star Names: Their Lore and Meaning (Revised ed.). New York: Dover Publications. pp. 67–72. ISBN 0486210790.</ref>

==Ths Star==

==Ths Star==

The true distance of the star was not known until the 1990's, and estimates beforehand varied from 96 light years away to some 1200 light years.    The [[Hipparcos]] satellite telescope finally established the distance of the star to be around 310 light years away.<ref name="simbad">http://simbad.u-strasbg.fr/simbad/sim-id?Ident=name+canopus</ref>  

The true distance of the star was not known until the 1990s, and estimates beforehand varied from 96 light years away to some 1200 light years.    The [[Hipparcos]] satellite telescope finally established the distance of the star to be around 310 light years away.<ref name="simbad">http://simbad.u-strasbg.fr/simbad/sim-id?Ident=name+canopus</ref>  

Canopus itself is a rare spectral class F0 Ia yellow-white [[supergiant]].  The star may be either evolving towards or away from red supergiant status, but such stars as Canopus are still poorly understood.  The star itself is 13,300 times as bright as our [[Sun]].  It is some 71 times the Sun's diameter, extending to within 90 percent of [[Mercury|Mercury's]] orbit, if it was in the center of our solar system, and some 8 to 9 times our Sun's mass.  The surface temperature of Canopus is estimated to be 7280 K, typical for a star in the F class.  The [[corona]] of Canopus though is some ten times as hot as out Sun's corona, and is a considerable source of [[x-ray|X-rays]].<ref name="illinois">http://stars.astro.illinois.edu/sow/canopus.html</ref>

Canopus itself is a rare spectral class F0 Ia yellow-white [[supergiant]].  The star may be either evolving towards or away from red supergiant status, but such stars as Canopus are still poorly understood.  The star itself is 13,300 times as bright as our [[Sun]].  It is some 71 times the Sun's diameter and some 8 to 9 times our Sun's mass.  If it was in the center of our solar system it would extend to within 90 percent of Mercury's orbit.  The surface temperature of Canopus is estimated to be 7280 K, typical for a star in the F class.  The [[corona]] of Canopus however is some ten times as hot as our Sun's corona, and is a considerable source of [[x-ray|X-rays]].<ref name="illinois">http://stars.astro.illinois.edu/sow/canopus.html</ref>

There are no know substellar companions of Canopus.  For an [[terrestrial planet|Earth-like]] world to exist comfortably with liquid water on its surface around Canopus, it was have to be around three times the distance [[Pluto]] is from the Sun.

There are no known substellar companions of Canopus.  For an [[terrestrial planet|Earth-like]] world to exist comfortably with liquid water on its surface around Canopus, it would have to be around three times the distance [[Pluto]] is from the Sun.

Canopus is in the [[helium]] burning phase of its evolution, depending on its true mass, the star may eventually [[supernova]] or it will fusing at its core before the fusion into [[iron]] required to cause a supernovae collapse.  If the latter is true, the star may end its life as a rare [[neon]]-[[oxygen]] [[white dwarf]] (most white dwarfs are mainly made up of carbon and oxygen).<ref name="illinois">http://stars.astro.illinois.edu/sow/canopus.html</ref>

Canopus is in the [[helium]] burning phase of its evolution.  Depending on its true mass, the star may eventually [[supernova]] or it will cease fusing elements at its core before the required fusion into [[iron]] needed to cause a supernovae collapse.  If the latter is true, the star may end its life as a rare [[neon]]-[[oxygen]] [[white dwarf]] (most white dwarfs are mainly made up of carbon and oxygen).<ref name="illinois">http://stars.astro.illinois.edu/sow/canopus.html</ref>

[[Category:Astronomy]]

[[Category:Astronomy]]