P1 - Topic 3 - Life Cycle Of Star Flashcards
What do stars initially form as?
Nebulas - a cloud of gas and dust
How does gas and dust spiral together?
The force of gravity
What does the force of gravity do to a nebula?
Pull together the dust and gas
What causes the temperature of a nebula to rise?
The gravitational energy being converted into heat energy
When the temperature gets higher enough what happens to hydrogen nuclei?
It undergoes thermonuclear fusion to form helium nuclei and give out massive amounts of energy
When a hydrogen nuclei undergo thermonuclear fusion, what is formed and given out?
A helium nuclei is formed and gives out massive amount of energy
How is a star born?
1) the force of gravity creates a nebula by pulling tigers he dust and gas
2) gravitational energy is converted into heat energy
3) when the temperature rises enough, hydrogen nuclei undergo thermonuclear fusions to form a helium nuclei and give out massive amounts of energy
When a star is born what dos it immediately enter?
It enters a long stable period where the heat create by nuclear fusion provides an outward pressure to balance the force of gravity pulling everything inwards
What is a star called when it enters a long stable period and how long does it last?
Main sequence star and it can last for several billion years
What is a nebula?
A cloud of dust and gas
In the core of a star, what eventually runs out?
Hydrogen
What happens what the hydrogen in the core of a star begins to run out?
The star swells into a red giant
Why does a red giant star become red?
Because the surface cools
How does a red giant star form?
When a main sequence star eventually begins to run out of hydrogen in the core, it swells into a red giant
The the sun a bit or small star?
Small
After becoming a red giant star, what kind of star does it become?
Planetary nebula and white dwarf
How does a red giant become a planetary nebula?
It becomes unstable and ejects layers of dust and gas as a planetary nebula
Does a a white dwarf eventually disappear?
Yes
Why does a white dwarf eventually disappear?
Because it cools down
What is a white dwarf star?
A hot dense solid core that is left behind when a small star becomes unstable and ejects its outer layers of dust and gas
What do big stars become after a red giant?
A supernova star
How does a supernova from?
They undergo more fusion and expand and contract server all times, forming heavier elements in various nuclear reactions. Eventually they’ll explode in a supernova
If a star is big enough what will it become after a neutron star?
A black hole
When do black holes form?
When the star is big enough to become one
What is a neutron star and how is it formed?
It is a very dense core which is left after an exploding supernova throws the outer layers of dust and gas into space
What is the life cycle of a big star?
Nebula Main sequence star Red giant Supernova Neutron star Black hole (if big enough)
What is the life cycle of a small star?
Nebula Main sequence star Red giant Planetary nebula White dwarf
