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justaguide eNotes educator| Certified Educator

The death of a star refers to the processes that take place after all the fuel required for fusion reactions in a star gets over. They differ based on the size of the star.

Most stars expand and form what is called a Red Giant when the hydrogen has been consumed. The fusion reactions continue with helium and heavier elements in a small space known as the core.

Once all the fuel is over, for a star which is approximately as large as our Sun, the core cools as a white dwarf and the gases which form the atmosphere move into space.

Stars larger than the Sun but not more than three times its size undergo what is called a supernova, which is a massive explosion that scatters most of what made up the star into space. Whatever remains, collapses into a small and very dense form that is known as a neutron star.

Even larger stars, also undergo a supernova, but what remains after the explosion collapses under its own mass into an infinitely small region that has a gravitational pull even light cannot escape from. These are known as black holes.

astrosonuthird | Student

According to the chandrasekhar limit. The sun has a hell lot of mass it increases in size day by day and becomes a red giant. After becoming a red giant at one point of time it runs out of fuel and either becomes a black hole or a neutron star. 

astrosonuthird | Student

when stars die they either become supergiant or white dwarf or can become even a blackhole when its all the nuclear fuel is used up.

astrosonu | Student

I think it becomes a white dwarf. If the stars mass is more than the three times of our sun, it will become an  supergiant or else if less a neutron star or a black hole.

krishna-agrawala | Student

What we call stars in common language are really huge balls of glowing gas in the sky. The object we call sun is just one such star that appears much bigger than other stars because of its closeness to the earth.

A star begins its life as a cloud of interstellar gas and dust. Over millions of years, the cloud of gas and dust contracts as gravity pulls it together into a ball. With this the pressure of the gas increases the centre of the ball becomes extremely hot. When the temperature reaches about 1,100,000 °C. the nuclear fusion reaction begins.  This produces energy that heats the gas that surrounds the centre, making it shine. This is when the star can be said to achieve maturity.

After this further changes take place in star leading to what can be described as death of a star. These changes are caused by depletion of the star's supply of hydrogen.  With this, the star's centre contracts, and the temperature and pressure at the centre rise, and that at the outer part gradually drops.  With increased pressure at the center, the star expands greatly and becomes a red giant.  What happens after this phase depends on how much mass the star contains.  A star with about the same mass as the sun throws off its outer layers. This forms a glowing gas shell called a planetary nebula.  The remaining core cools and becomes a white dwarf.

A star with more than about three times the mass of the sun transform into a supergiant.  Elements as heavy as iron forme inside the star, which subsequently explode into a supernova.  When less than three times the mass of the sun remains after this explosion, it becomes a neutron star.  Otherwise the star collapses and forms a black hole.