Red Giant

Red Giant

Red giants are the ending stages of a star which has exhausted all its hydrogen at its core and has started to consume the hydrogen from its outer shell. Only the stars with smaller mass i.e. 0.3 to 8 solar masses become red giant at the end of its life.

When the hydrogen in the inner core of the star is fully consumed then the nuclear fusion reaction starts shifting in the outer shells. When the outermost shells of the star start burning, then the core contracts due to its own gravity. This creates an empty space between the core and the outer shell. The outer shell of the star keeps expanding. This expansion is so massive that its radius becomes 100 times bigger than the radius of our sun. Though the core doesn’t burn, even then it is hotter than the expanding shell. The outer shell radiates lesser energy than our sun still it is much brighter because of its extra-large size. The surface temperature of this outer envelope is low, that is why it appears reddish orange in color. Its life is too short as compare to its life as a normal star and as the time passes, the core contracts more and the envelope expands. When this expansion exceeds its limit, it explodes leaving behind a fade cloud of dust and a core without any activity.

The stars which are larger than 8 solar masses don’t convert into a red giant as their gravitational pull is too high to allow any expansion in the outer shell. Stars with a very high mass simply become a black hole.

Related Articles: Astronomical Unit, Supernova, Nebula, Exotic Star, Black hole, White Dwarf, White hole, Flipping of Solar Magnetic Poles, Space-time

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