What would happen if VY Canis Majoris went Nova?

Question

It's a really really big star so what will happen when it dies? Will other star systems be in danger?

Answer 1

When VY Canis Majoris dies, it will die as a core-collapse supernova or even a hyper-nova depending on it's mass and composition. It's huge size does not necessarily mean it will explode as a hyper-nova and give rise to a gamma ray burst when some or all of the star becomes a black hole. Even so, it's much more likely to explode as a core-collapse supernova that will produce a neutron star or a black hole depending on what happens when it's core is converted into iron. When that happens, the outer layers will initially be ejected back into space at speeds of 5,000 miles per second or more, and the wreckage will outshine the entire galaxy for weeks or months. If VY Canis Majoris had any planets, they would be at the minimum ejected into space due to the sudden loss of 90 percent or more of the star's mass back to space. Their atmospheres and surface water if present would be flash boiled away into space, and likely their surfaces would melt from being hit with billions of times more energy than they received before. It's indeed possible they would simply be vaporized in the explosion. If there are any life bearing planets within a few light years of VY Canis Majoris when it blows, all life would be destroyed. Any inhabited planets within 30 or 50 light years of the explosion will either be sterilized or suffer severe mass extinctions due to the massive blast of gamma and x-rays disrupting the ozone layer. Dangerous, even deadly doses of radiation will kill or injure any complex, multi-cellular life forms but single cell microbes can withstand radiation fields that would instantly kill humans and most other higher forms of life. Star systems farther away would be exposed to much more ionizing radiation and cosmic rays, which would induce mutations and leave traces in the soil, ice sheets and oceans, but would not trigger wide spread die offs of species wholesale.  From several hundred light years away, VY Canis Majoris' demise would be no threat to a habitable planet, but a bonanza for astronomers interested in the lives and deaths of stars and how they made our own existence possible. If however, VY Canis Majoris is massive enough  and has the right composition to explode as a hyper-nova, the resulting gamma ray burst will destroy life on planets caught in the jets spat out by the newly born black hole thousands of light years away. These jets form along the doomed star's axis of rotation, and are highly focused like laser beams. If an inhabited planet is not in the way, it would survive unharmed unless it was in close proximity to the supernova. A planet or life on that planet caught in the jet is doomed. Planets within a 100 light years would melt or vaporize from the jet's onslaught, which are composed of high energy plasma moving at nearly the speed of light.They are nature's ultimate death ray, much like the Death Star out of the Star Wars movies.

Answer 2

A black hole will be formed!

Answer 3

It's too far away to matter-- but it would probably be visible during the daytime.... for several months.

Answer 4

VY Canis Majoris is 5000 light years from Earth, so if were to supernova it would be very bright in our skies but would not affect Earth or our solar system.

However, any stars or solar systems within about 100 light years of VY would be flooded with radiation (gamma, xrays, UV, etc.) and life on a planet there could be destroyed (or at least seriously damaged).

Any planets around VY would likely be vaporized or ejected from that system by the explosion.