Life cycle of a star?!?!!?!?

 
     This is an image of a stellar nursery, from these cold clouds of stellar matter protostar form as they collapse under gravitational disturbances.that is it will stay the same until the kinetic energy is balanced with
the potential energy of the internal gravitational field.
     when these protostars start to collapse and the pressure and temperature the cloud, it starts to form a disc
and nuclear reactions start to take place.
  At this point some protostars are rather too small and don't achieve nuclear reactions and are called failed stars or brown dwarfs.
  All the other protostars which have achieved nuclear reactions show very unstable behaviour like rapid rotation strong wind and eject a lot of nuclear materials at the poles and slowly stabilise.
  In stars have more than about 0.08 solar masses form a star having nuclear reactions. The core of the stars literally start collecting the stellar clouds during this time some of the hot nuclear substance fly off to form planets which individually start collecting the stellar clouds around them. After this formation of stars and planets, the stars , enter the main sequence, every star spends about 90% of their life in this stage.

•  Stars lesser than 1 solar mass collapse to form a dim black dwarf.
•  Sun like stars (1solar mass) evolve or more precisely get swollen to form a red giant, the outer layers  form the planetary nebulae the heavy elements now help the core to become a white dwarf  which will  be inside the planetary nebulae.
• Stars having more than 8 solar masses evolve in a super giant, explodes as a supernova, smaller  remnants become neutron star or stars that are of almost the size of earth and larger remnants become a black 

          know more on black holes

       Here is a video from nasa.gov ,

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