The Life and Death of a Star

Birth of Low and Medium Mass Stars

• Nebula– Large cloud of gas and dust.

• Protostar– When the cloud of gas and dust contract together

to form a body which begins to resemble a star.

• Main Sequence Star– A star is formed when nuclear fusion begins in its

core. – Low Mass stars can burn up to 200 billion years.– Medium Mass stars can burn up to 10 billion years

Death of Low and Medium Mass Stars

• Red Giant– Star expands to several times its size and becomes

brighter.

• Planetary Nebula– Outer layers of the star’s atmosphere begin to

drift away.– Only the core of the star is left.

• White Dwarf– The remaining hot core of the star.

• Black Dwarf– A black corpse of the original star.

Birth of High Mass Stars

• Nebula– Large cloud of gas and dust.

• Protostar– Larger amounts of dust and gas contract together.

• Main sequence high mass star– Much larger and burns fuel quicker.– Average life span is 10-15 million years.

Death of High Mass Stars

• Supergiant– Star runs out of fuel and expands.– Much larger and brighter than a red giant.

• Supernova– Core of supergiant collapses under its weight.– Core explodes shinning millions of times brighter.

• Neutron Star– Small, dense remains of the high mass star after a

supernova.– Pulsars-spinning neutron stars which “pulsate”

radio waves.

OR

• Black hole – An object with gravity so strong that nothing can

escape it.– Extremely dense.