Different stars take different amounts of time to progress through their life. Stars such the sun take about 50 billion years to mature into adulthood. Stars are fueled by the nuclear fusion of hydrogen and helium deep in their interiors. The outflow of energy from the centre of stars provides enough pressure to keep the star from collapsing under its own gravity.
The life of average stars: Average stars begin their life as a protostar, in which they then mature into main sequence stars. Average stars then proceed their formation into a red giant. These stars are very bright and have a cool surface. Red giants form as the hydrogen fuel runs out in its core. A red giant will then form into a planetary nebula as the helium like hydrogen has all fused. Once this process is complete the star will enter its later years... The life of massive stars: Massive stars also begin as protostars and mature into main sequence stars. Massive stars then evolve into red super giants, which are the biggest stars known to human. Massive stars also complete the same process of nuclear fusion throughout their life as a main sequence star and red super giant. Red Giants: Red giants are just one of the many types of stars. They form from main sequence stars and evolve into a planetary nebulae. When the hydrogen within a main sequence is exhausted due to nuclear fusion, a shell of nuclear reactions will start to move outwards into its atmosphere. Therefore the star expands and cools, turning much redder. This forms a red giant. Once a star is at this stage, conditions are correct to begin nuclear fusion once again except now using helium as a fuel instead of hydrogen. Once the helium has all fused, the red giant becomes a planetary nebula and then a white dwarf as it shrinks, cools and begins to die. |
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