Why does a supernova occur?

Answer 1

A supernova (pl. supernovae) is a stellar explosion which produces an extremely bright object made of plasma that declines to invisibility over weeks or months. A supernova briefly outshines its entire host galaxy. It would take 10 billion years for the Sun to produce the energy output of an ordinary Type II supernova.[1]. The Sun is notably too small to ever become a supernova—rather it will become a White Dwarf (see Chandrasekhar limit).

There are several different types of supernovae and two possible routes to their formation. A massive star may cease to generate fusion energy from fusing the nuclei of atoms in its core, and collapse under the force of its own gravity to form a neutron star or black hole. Alternatively, a white dwarf star may accumulate material from a companion star until it nears its Chandrasekhar limit and undergoes runaway nuclear fusion in its interior, completely disrupting it. This second type of supernova is distinct from a surface thermonuclear explosion on a white dwarf, which is called a nova. In either type of supernova, the resulting explosion expels much or all of the stellar material with great force.[2]

The explosion drives a blast wave into the surrounding space, forming a supernova remnant. One example of this process is the remnant of SN 1604, shown to the right.

"Nova" is Latin for "new", referring to what appears to be a very bright new star shining in the celestial sphere; the prefix "super" distinguishes this from an ordinary nova, which also involves a star increasing in brightness, though to a lesser extent and through a different mechanism.

Answer 2

All during the lifetime of any star a constant struggle goes on between the star's gravity and its temperature. Its gravity continually tries to make the star collapse, while its temperature tries to cause it to expand. As long as the two forces are balanced the star remains stable.

When a star uses up all its fuel and its nuclear "furnace" shuts down the star cools. At that point gravity takes over and the star shrinks in size. If the star is between 1.5 to 4 times more massive than our sun, the shrinkage happens all at once--in less than a second. The mass of the star crashes together and an immense explosion happens. That explosion is called a supernova.

Answer 3

When a star completes its term of life, it exhausts its resources of energy by exploding and transforming into a white dwarf. The final moments of a star's life results in a spectacular spaceshow known as the Supernovae

Answer 4

A gravitational collapse supernova erupts when a star at least eight times more massive than our sun runs out of fuel.