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VY Canis Majoris



VY Canis Majoris


Distance to Earth: 4,892 light years
Surface temperature: 3,000 K
Mass: 59.67E30 kg (30 Solar mass)
Radius: 987,600,000 km (1,420 R☉)
Right ascention: 7h 22m 58s
Constellation: Canis Major

VY Canis Majoris, named for the constellation  in which it resides, is fitful and restless, it’s entire lifespan  only a few million years.  It is a very bright red giant star,  its luminosity due to enormous mass loss.  This star is losing  billions of tons of material every day which surrounds it like a  death shroud.

The reason for this mass loss is poorly understood, but it is  believed to be due instabilities in the interior and exterior  layers of the star.  These instabilities are usually the progenitor  of a supernova.

VY Canis Majoris has already shed over half of its original mass.  It is in the final throes of death and could explode at literally,  any time.

If it exploded today, some 4,900 light years away, the blast wave  would slam into the surrounding envelope of material with a  velocity of a few thousand kilometers per second and produce what  is known as a Type IIn supernova.

Also known as a core collapse supernova, these explosions result  when the interior of the star can no longer support it and it  collapses at rates of up to 70,000 kilometers per second.

This rapid collapse heats the interior of the star, producing  high energy gamma rays that can decompose iron nuclei created  during the lifetime of the star into helium and free neutrons and  neutrinos.  As the core collapses, electrons and protons are  squeezed together, producing neutrons and more neutrinos.

Since neutrinos rarely interact with other forms of matter, they  escape, accelerating the core collapse and slams into the outer  layers of the star, triggering the supernova explosion.

Milliseconds after the collapse began, the core has detached  itself from the from the outer layers of the star.  With most  Type II supernovae, this crush is finally halted by the strong  nuclear force, preventing the neutrons from packing together any  tighter.


A neutron star is born.

But VY Canis Majoris is so large, many astronomers believe its  fate may be even more spectacular.  It may die in what is called  a hypernova.  These outbursts contain more energy than 100  supernovae, emitting enormous quantities of gamma rays when it  occurs.

These gamma rays can actually pose a threat to nearby stars and  planets, and depending on their distance, are strong enough to  destroy any life that may reside there.  Fortunately for us, if  this is in fact VY Canis Majoris fate, it is so far away that  Earth will not be affected.

Finally, the core from this hypergiant is so massive that its  collapse crushes even the neutrons together, the collapse is so  inexorable nothing can stop it, leaving behind a black hole.

The spectacle of exploding stars peppers our history – ancient  peoples have recorded many of them. There is roughly one supernova  in our galaxy every fifty years.

Luckily for any other life that may exist in our galaxy, hypernova  occur even less


VY Canis Majoris

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