P16.2 The life history of a star Flashcards
What are the key features of a red giant star?
At this stage helium and other light elements in the core fuse to form heavier elements
Why does the star collapse?
Due to no more light elements in the core - fusion stops and no more radiation is released - Because of its own gravity it collapses on itself
How does a white dwarf form?
As the star collapses it heats up and turns from red to yellow to white
A white dwarf is hot - dense - white star much smaller in diameter than it was before
How does a black dwarf form?
When stars the such as the sun fade out - go cold and become black dwarfs
What happens to stars that are much bigger then our sun?
These stars swell out to become red super giants than collapse
In the collapse the matter surrounding the star’s core compresses more and more
The compression suddenly reverses in a cataclysmic explosion called a supernova
How are light elements formed?
Formed by the fusion in stars
Stars such as the sun fuse hydrogen into helium and similar small nuclei - including carbon nuclei
How does larger nuclei get formed?
When the star becomes a red giant it fuses helium and other small nuclei into larger nuclei
Why cant nuclei larger than iron be formed?
Nuclei larger than iron nuclei cannot be formed by this process because too much energy is needed
How do heavy elements form?
When massive stars collapse then explodes as supernova
The enormous force of the collapse fuses small nuclei into nuclei bigger than iron nuclei
Explosion scatters the elements throughout the unvierse
What is left after a supernova?
