Lifecycle of a star : Birth to Death

STARS AND PLANETS 

Star

A star is a luminous and biggest object in the universe that emit light naturally. Sun is also a star. The study of birth , life and death of a stars is called stellar evolution. First stage in the birth of star is called protostar and the death of star is called supernova. 

FORMATION OF A STAR BY CLOUD OF DUST

How stars are formed ?

Stars are made by cloud of gases and dust that scattered throughout the galaxies. The cloud of dust is called the orion nebula. As gravitational force of attraction applied on cloud they collapses and when cloud collapse the material at the center get heat up so that all stars and planet have high temperature at core.

A star build by continuous process of gravitational pull cloud collapse to make its size bigger. The size of star (or mass of a star) reaches from 15 to 130 solar masses. At center the temperature gets extremely high, it tigger the fusion reaction. All the material that has fallen in then evolves into a hot and brighter star like sun. The star will continue to emit light  (or shine) as  Long as there is hydrogen gas to fuse through nuclear reaction. 

How a star spend its life ?

A star lives 10 billion years approx. but the life of star is depend on it's mass. The larger it's mass , the shorter it's life. It takes 50 million years to be a mature star from beginning to adulthood. A smallest star is known as a red dwarf , it may contain as little as 10% the mass of sun and emit only 0.01% as much energy , glowing at temperature between 3000K  to 4000K. 

When the star like sun reach the red gaint phase of their core temperature increase as carbon atoms are formed from the fusion of helium atom and gravitational power.

SUPERNOVA : DEATH OF A STAR 

DEATH OF A STAR

Death of a star is called supernova. When the supergaint  (star) destroy itself with huge explosion then supernova happened.  

Death of a star is happening when the helium fuel runs out the core will expand and cool. The core cool down into a white dwarf and then into a black dwarf. There is also a chance that star can convert into a black hole after death. Which attracts any matterand energy come near it. 

A supernova is the biggest explosion that human have ever seen. Each blast extremely brighter and super power full approx 1028 megaton nuclear bomb and also it release energy about 10 time more energy than the sun will emit in its entire lifetime. 

LIFECYCLE OF A STAR

Lifecycle of a star in one view

Step I:- A cloud of gas and dust collapse due to gravity , creating a protostar.

Step II:- Gravitational energy give power to the young star. 

Step III:- Nuclear fission occurs. The main sequence star may live million or billion of years.

Step IV:- The star expands into a red gaint when the star's hydrogen level drop.

Step V:- Different fusion process occurs then star start to expand , cool and loss the mass each time.

Step VI:- Fusion stops and a supernova explosion occurs. 

Step VII:- Depending on the original star's mass , either a black hole or a neutron star is formed. 

These steps repat in continuous way.

 Using the above background information, (and additional sources of information from the dictionary).

-By Mratyunjay Saxena