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Introduction
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Activities
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Quiz
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Conclusion
What I learned
Throughout their lives, stars go through a process of change called stellar evolution.
The main stages of this process are:
❖ Star birth: stars are born in clouds of gas and dust called nebulae. The main building block in them is hydrogen. The initial stage in their formation is the protostar. When the temperature and pressure in the core of the protostar reach critical values that defy gravity, nuclear reactions begin and a star is born.
❖ Main sequence: this is the main stage of the life of stars. The length of time a star stays in the main sequence depends on its mass: more massive stars burn through their fuel faster and have a shorter lifetime.
❖ Red giant: When the hydrogen fuel in the core is exhausted, the star begins to expand and cool, becoming a red giant..
❖ Final stages: once it has exhausted the hydrogen fuel in its core and nuclear reactions stop, the star dies.
Depending on its mass, the final stage of the star can be:
- for medium-mass stars, like the White Dwarf Sun;
- for massive stars – explode as supernovae, followed by a neutron star or black hole;
- for low-mass stars: they gradually cool and shrink, becoming black dwarfs.
Studying stellar evolution helps us understand the origin and future of the Universe.
