Stars
High-mass stars, those with at least eight times the mass of the Sun, go through a distinct evolutionary process compared to lower-mass stars. They burn through their hydrogen fuel quickly, generating enormous pressure and temperature in their cores. As the core depletes hydrogen, fusion progresses to heavier elements like helium, carbon, oxygen, and beyond, forming an onion-like layered structure.
Unlike in lower-mass stars, fusion in high-mass stars can continue up to iron. However, iron fusion does not release energy; instead, it absorbs energy, causing a sudden loss of pressure support. This results in core collapse, leading to a dramatic supernova explosion.
The aftermath of a supernova depends on the remaining mass. If the collapsed core is between 1.4 and 3 times the Sun's mass, it forms a neutron star—an incredibly dense object where protons and electrons merge into neutrons. If the core is more massive, it collapses further into a black hole, where gravity is so intense that not even light can escape.
Supernovae play a crucial role in cosmic evolution by dispersing heavy elements into space, enriching future generations of stars and planetary systems.
Now please read these sections from the Openstax Astronomy textbook.
Self-Evaluating Questions
Try answering these questions after completing the reading. If you find any difficult to answer, revisit the textbook to reinforce your understanding.
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How do temperature and pressure affect their fusion process?
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Why does fusion continue up to iron but not beyond?
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What happens when iron fusion begins to absorb energy instead of releasing it?
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How do charged particles from the Sun create auroras on Earth?
What are the potential risks of solar wind for satellites and astronauts?
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What role do they play in forming the elements needed for planets and life?