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[[Image:Zeta_Puppis.jpg|thumb|right|250px|Artistic depiction of Zeta Puppis]]

'''Zeta Puppis''', also called by its traditional name '''Naos''' from the Greek ναύς "ship", or less commonly, '''Suhail Hadar''', is one of the hottest stars in the galaxy, one of the few rare class O stars visible in the night sky, and is the second brightest such star in terms of its apparent magnitude (only [[Zeta Orionis]] appears brighter). It is located in the constellation of [[Puppis]].  Zeta Puppis is located 1,093 light years away according to the 2008 data from the [[Hipparcos]] mission.<ref>Maíz Apellániz, J.; Alfaro, E. J.; Sota, A. (2008). Accurate distances to nearby massive stars with the new reduction of the Hipparcos raw data. arΧiv:0804.2553</ref>  

| rightascension  =08^h 03^m 35.04754^s<ref name=simbad>[http://simbad.u-strasbg.fr/simbad/sim-id?Ident=zeta+puppis&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id Zeta Puppis] from the [http://simbad.u-strasbg.fr/simbad SIMBAD Astronomical Database]</ref>

| distance        =1,093 ly<ref name=arxiv>Maíz Apellániz, J.; Alfaro, E. J.; Sota, A. (2008). Accurate distances to nearby massive stars with the new reduction of the Hipparcos raw data. [https://arxiv.org/abs/0804.2553 arΧiv:0804.2553]</ref>

| constellation  =Puppis

| type            =Supergiant{{!}}Blue supergiant

| dimensions      =

| magnitude      =Apparent Mag: +2.21<ref name=constellation-guide>[http://www.constellation-guide.com/constellation-list/puppis-constellation/ Puppis Constellation] from constellation-guide.com</ref><br/>Absolute Mag: -5.41<ref>From definition of absolute magnitude, using apparent magnitude (+2.21) and distance (1,090 ly) given here.</ref>

'''Zeta Puppis''', also called by its traditional name '''Naos''' from the Greek ναύς "ship", or less commonly, '''Suhail Hadar''', is one of the hottest stars in the [[Milky Way|galaxy] and one of the few rare class O stars visible with [[binoculars]] in the night sky.<ref name=constellation-guide/> It is the second brightest such star in terms of its [[Star magnitude|apparent magnitude]], with only [[Zeta Orionis]] appearing brighter. Located in the [[constellation]] of [[Puppis]], Zeta Puppis is located 1,093 light years away according to the 2008 data from the [[Hipparcos]] mission.<ref name=arxiv/>

Zeta Puppis is a blue [[supergiant]] star of spectral class O5IAf, making it one of the hottest stars in the [[Milky Way|galaxy]] with a surface temperature of 42,400K (in comparison, the [[Sun]] has a surface temperature of 5,780 K).<ref>Lamers & Cassinelli 1999, accurate to 200 K</ref>  The star’s mass is 59 times that of our Sun, and 20 times its diameter.

Zeta Puppis is a blue [[supergiant]] star of spectral class O5IAf, making it one of the hottest stars in the [[Milky Way|galaxy]] with a surface temperature of 42,400 K (in comparison, the [[Sun]] has a surface temperature of 5,780 K).<ref>Lamers & Cassinelli 1999, accurate to 200 K</ref>  The star’s mass is 22.5 times that of our Sun, and 14 times its diameter.<ref name=constellation-guide/> However there is large uncertainty in these measurements due to an uncertainty in the stars distance, so some put these higher at a mass of 40 solar masses.

Because Zeta Puppis is an exceptionally large class O [[supergiant]], it is one of the brightest stars in the [[Milky Way|galaxy]] in terms of absolute magnitude, at -5.96. The star is 21,000 times as luminous as our Sun visually.  However, because it is a class O blue star, most of the radiation from the star is in the [[ultraviolet]]. When this is considered, the star is 790,000 times more luminous then the [[Sun]] overall.

Since Zeta Puppis is an exceptionally large class O [[supergiant]], it is one of the brightest stars in the [[Milky Way|galaxy]] in terms of absolute magnitude, at -5.96. The star is 21,000 times as luminous as our Sun visually.  However, because it is a class O blue star, most of the radiation from the star is in the [[ultraviolet]]. When this is considered, the star is 790,000 times more luminous then the [[Sun]] overall.

Because of its temperature and luminosity, if Zeta Puppis was at the same distance as [[Sirius]] from our [[Solar System]], it would appear as bright as a quarter-moon.  If Zeta Puppis was our Sun, the [[Earth]] would have to be 450 AU away in order to maintain the same temperature and climate, or about 11 times the mean distance of [[Pluto]] from our Sun.

Because of its temperature and luminosity, if Zeta Puppis was at the same distance as [[Sirius]] from our [[Solar System]], it would appear as bright as a quarter-moon.  If Zeta Puppis was our Sun, the [[Earth]] would have to be 450 AU away in order to maintain the same temperature and climate, or about 11 times the mean distance of [[Pluto]] from our Sun.

Because it is so bright and hot, it is fusing [[helium]] into [[carbon]] and [[oxygen]] in its core.<ref name="illinois">http://www.astro.illinois.edu/~jkaler/sow/naos.html</ref>

As it is so bright and hot, it is [[fusion|fusing]] [[helium]] into [[carbon]] and [[oxygen]] in its core.<ref name=illinois>[http://stars.astro.illinois.edu/sow/naos.html Naos] from stars.astro.illinois.edu</ref> The star generates a very strong [[stellar wind]] with a velocity between 2,300-2,500 km/s<ref name=constellation-guide/><ref name=illinois/> This results in the star loosing around a millionth of a [[solar mass]] of material each year. This may sound small but it is over 10 million times more than the [[Sun]] looses and is some 1.99×10²⁴ kg/yr.

Zeta Puppis is a fine example of a class O "runaway" star and is moving at a speed of over 100 kilometers a second.

Zeta Puppis is a fine example of a class O "runaway" star and is moving at a speed of over 100 kilometers a second.<ref name=illinois/> This is likely to it having been ejected from another star system. Like many runaway stars, Zeta Puppis rotates very quickly, at some 220 km/s around its [[equator]] which is 100 times faster than the Sun.<ref name=illinois/>

[[Category:Astronomy]]

==References==

==References==

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