P1.3 Life Cycle Of Stars Flashcards
What causes the gas and dust to spiral in together?
The force of gravity
Nebula
What’s do stars initially form from?
Clouds of dust and gas
NEBULAS
What causes the temperature to rise?
When spiralled together
The gravitational energy is converted into heat energy causing the temperature to rise
(Nebula)
What happens when the temperature of the nebula gets high enough?
Hydrogen nuclei undergo thermonuclear fusion to form HELIUM nuclei and give out massive amounts of energy. (Star is born)
MAIN SEQUENCE STAR
What happens when the star is in a long stable period?
Heat created by the nuclear fusion provides an outward pressure to balance the force of gravity pulling everything inwards.
(In this stable period it’s called a main sequence star and can last for several billion years
What happens when the hydrogen in the core begins to run out ?
The star swells into a red giant (it becomes red and the surface cools)
RED GIANT
What Happens to small or medium stars after the red giant stage?
It becomes unstable and ejects its outer layer of dust and gas as a planetary nebula.
(This will happen to the sun)
After a planetary nebula is formed what happens?
A hot dense solid core is left behind forming a white dwarf which just cools down and eventually disappears
What happens to big stars after the red giant stage
Big stars start to glow brightly again as they undergo more fusion and expand and contract several times, or mint heavier elements in various nuclear reactions. Eventually they will explode in a supernova.
What happens after an exploding supernova is formed?
The exploding supernova throws its outer ayers of dust and gas into space, leaving behind a dense core called a NEUTRON STAR. If the star is four times its original size it will become a BLACK HOLE.
