Death of stars

 Death of stars...

         Reading this word might give no reaction on your face, but death of star is very important thing to study in the astrophysics. As the stars live afterlife differently depends upon how there life was and also depending upon there size there afterlife future can be decided. One must also amazed by reading that we are the remnant  of such dead stars. No element having atomic number more than 27 that is iron can be made inside living stars. Stars have to die to create such elements and we know these elements are the part of our body, that means we are the remnant of these dead stars.

         Death of the star can be predicted by the Chandrashekhar limit. 

Stellar Nebula	Average Star	Red Giant	Planetary Nebula	White Dwarf
Stellar Nebula	Massive stars	Red super giants	Super Nova	Black Hole
				Neutron star

      As shown in above table Stars can live different types of lives. If the star is having large mass, it will lose its energy very fast in the form of radiation and can explode as a Super nova. But if the Star is small like the sun, it will live longer life. such stars uses their fuel with average rate and die as a White dwarf. 

    Stars are born from the Stellar nebulae which we can consider as a clouds of the hydrogen gas. the gas becomes spherical because of its own gravity. Starts rotating around itself and the nuclear reactions get stared in the center. that means hydrogen starts converting into the helium or higher elements. and we now call it as a star. 

    The conversion of lighter elements into heavier on keep going on un till the formation of the iron. the iron have very stable nucleus so it need very large energy which cannot be supplied by the ordinary star. now the star is about to die.

    While converting the elements into heavier one, all the heavy elements produced in the process get accumulated in the center and the light elements starts floating. and because of gravity the canter starts shrinking. also because of increase in temperature the outer layer of the stars expands and we call it either Red giant or the super giant. 

    At the end the contraction of the center and the expansion of the outer layer is so large that the star explodes. Depends upon how much energy is given out by the star, we call this explosion as the Super nova or the planetary nebula.

    If the nucleons remaining the remaining star still follows Pauli's exclusion principle, the nuclear reactions stops and star eventually cools down and we call it as a white dwarf. There is another possibility nucleons do not follow the Pauli's exclusion principle and goes on shrinking where almost all electrons and protons becomes neutrons. we call it the neutron stars. Now think that gravity is so strong that it cannot stop falling into itself. Star get imploded and becomes black hole. 

    Being dead as a black hole is interested way to die and astrophysicists get interested in studying them with more efforts. Dr. Stephen Hawking put his life into the study of the black hole when he was not even able to walk or talk.

    Studying Life of stars gives us idea about future of our solar system. We will se more about each stage of their life in another blog.