P2 - Stars

Question 1

Describe and explain the life cycle of a star.

Answer 1

Nebula

Made up of dust and gas. Gravity pulls it all together which turns Gravitational Potentials Energy into Kinetic which turns into heat.

Protostar

There is lots of gravitational potential energy which turns into kinetic. Particles collide to produce heat. The star is not yet hot enough to do nuclear fusion.

Main Sequence Star

The star has become hot enough for nuclear fusion. It fuses hydrogen to helium. The star is stable because the inward and outward forces (radiation pressure and gravity) are stable.

STARS LIKE OUR SUN/REGULAR STARS

Red Giant

The star begins to run low on hydrogen. This forces it to begin fusing heavier elements eg. helium. It starts getting cooler, redder and expands.

White Dwarf

The White Dwarf is the core of the star. It is smaller and hotter than the red giant. The outer layers of the star have drifted off.

Black Dwarf

The star has cooled until it has stopped glowing.

MASSIVE STARS

Red Supergiant

The star begins to run low on hydrogen. This forces it to fuse heavier elements up to iron. It becomes cooler, redder and expands.

Supernova

In a supernova it fuses elements heavier than iron (eg. gold) and throwns them out into the universe in a big explosion.

Neutron Star -> Low Mass Supernova

Black Hole -> High Mass Supernova.