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'''VY Canis Majoris''' is a red [[hypergiant]] star and an irregular pulsating variable located in [[Canis Major]].  The [[star]] is the largest known, and also one of the most luminous.  It is estimated to be some 4,000 [[light year|light years]] away.  Unlike many stars that are part of a multiple star system, VY Canis Majoris is a single [[star]] without any known companions.

'''VY Canis Majoris''' is a red [[hypergiant]] and an irregular pulsating variable [[star]] located in [[Canis Major]].  The [[star]] is the largest known, and also one of the most luminous.  It is estimated to be some 4,000 [[light year|light years]] away.  Unlike many stars, which are part of a multiple star system, VY Canis Majoris is a single [[star]] without any known companions.

Although in absolute magnitude, VY Canis Majoris is extremely bright; its apparent magnitude is only 7.9, making it invisible to the unaided eye.  The first mention of the star is in the star catalog of [[Jérôme Lalande]], on March 7, 1801 as a 7th magnitude star.<ref>Robinson, L. J. (December 7, 1971). "Three somewhat overlooked facets of VY Canis Majoris". Commission 27 of the I. A. U., Information Bulletin on Variable Stars (Konkoly Observatory, Budapest) (599)</ref>  During the 19th century additional observations revealed VW Canis Majoris was a red star and that it was fading over time.

Although in absolute magnitude VY Canis Majoris is extremely bright, its apparent magnitude is only 7.9, making it invisible to the unaided eye.  The first mention of the star is in the star catalog of [[Jérôme Lalande]], on March 7, 1801, as a 7th magnitude star.<ref>Robinson, L. J. (December 7, 1971). "Three somewhat overlooked facets of VY Canis Majoris". Commission 27 of the I. A. U., Information Bulletin on Variable Stars (Konkoly Observatory, Budapest) (599)</ref>  During the 19th century, additional observations revealed VW Canis Majoris was a red star and that it was fading over time.

In 1976, it was discovered that the star was located at the edge of a large molecular cloud.  VW Canis Majoris itself was at the tip of the rim of the cloud and they both share the same velocity, the star then may be associated with the cloud.<ref>Lada, Charles J.; Reid, Mark J. (January 1, 1978). "CO observations of a molecular cloud complex associated with the bright rim near VY Canis Majoris". The Astrophysical Journal (American Astronomical Society) 219: 95-104.</ref>  Further measurements of the cloud in 2007 revealed it was prolific at creating compound molecules such as hydrogen cyanide (HCN), silicon monoxide (SiO), sodium chloride (NaCl) and a molecule, phosphorus nitride (PN).  The phosphorous molecules are the most interesting to astronomers as phosphorous is relatively rare in the universe, but an essential ingredient to life as it is part of [[DNA]] and [[RNA]], as well as ATP, an energy storing molecule<ref>http://www.daviddarling.info/encyclopedia/V/VY_Canis_Majoris.html</ref>.

In 1976, it was discovered that the star was located at the edge of a large molecular cloud.  VW Canis Majoris itself was at the tip of the rim of the cloud and as they both share the same velocity, the star then may be associated with the cloud.<ref>Lada, Charles J.; Reid, Mark J. (January 1, 1978). "CO observations of a molecular cloud complex associated with the bright rim near VY Canis Majoris". The Astrophysical Journal (American Astronomical Society) 219: 95-104.</ref>  Further measurements of the cloud in 2007 revealed it was prolific at creating compound molecules such as hydrogen cyanide (HCN), silicon monoxide (SiO), sodium chloride (NaCl) and phosphorus nitride (PN).  The phosphorous molecules are the most interesting to astronomers, as phosphorous is relatively rare in the universe but an essential ingredient to life, as it is part of [[DNA]] and [[RNA]], as well as ATP, an energy storing molecule<ref>http://www.daviddarling.info/encyclopedia/V/VY_Canis_Majoris.html</ref>.

The star is classified as M3-m5e-la making it a red [[hypergiant]], late in its [[stellar evolution]].  The star was once a class O star when it was on the main sequence, likely at 30 to 40 times the mass of our [[Sun]].<ref>Wittkowski, M.; Langer, N.; Weigelt, G. (October 27, 1998). "Diffraction-limited speckle-masking interferometry of the red supergiant VY CMa". Astronomy and Astrophysics (European Southern Observatory) 340: 39-42.</ref>  The star is estimated to be 500,000 times the luminosity of our [[Sun]].  It is estimated to be some 1800 times to 2100 times the size of the sun in radius<ref>http://arxiv.org/abs/astro-ph?papernum=0610433</ref>. If VW Canis Majoris was our star, it would extend to the orbit of [[Saturn]].  So large, a beam of light would take 8 hours to circumnavigate the star. Like all [[hypergiants]], it has a very low density and is only some 30 to 40 times the Sun’s mass.

The star is classified as M3-m5e-la making it a red [[hypergiant]], late in its [[stellar evolution]].  The star was once a class O star when it was on the main sequence, likely at 30 to 40 times the mass of our [[Sun]].<ref>Wittkowski, M.; Langer, N.; Weigelt, G. (October 27, 1998). "Diffraction-limited speckle-masking interferometry of the red supergiant VY CMa". Astronomy and Astrophysics (European Southern Observatory) 340: 39-42.</ref>  The star is estimated to be 500,000 times the luminosity of our [[Sun]].  It is estimated to be some 1800 times to 2100 times the size of the sun in radius<ref>http://arxiv.org/abs/astro-ph?papernum=0610433</ref>. If VW Canis Majoris was our star, it would extend to the orbit of [[Saturn]].  VY Canis Majoris is so large, a beam of light would take 8 hours to circumnavigate the star. Like all [[hypergiants]], it has a very low density and is only some 30 to 40 times the Sun’s mass.

VW Canis Majoris is not without controversy.  Some scientists argue that the star is not as large as thought, but instead is a red [[supergiant]] that is some 600 times the radius of the Sun’s.<ref>http://arxiv.org/abs/astro-ph?papernum=0604253</ref>

VW Canis Majoris is not without controversy.  Some scientists argue that the star is not as large as thought, but instead is a red [[supergiant]] that is some 600 times the radius of the Sun’s.<ref>http://arxiv.org/abs/astro-ph?papernum=0604253</ref>