Life Cycle of Stars
by Cheyenne Eldridge
Interstellar Medium
Material that fills space between stars
Gas and Dust
Betweens the starsFirst Stage of Star Life Cycle
hydrogen (97%) and helium (3%)
Nebula is a cloud of dust and gas. There are a bunch of different regions that use gravity to make little “clumps” of gas and dust. Those little clump things are called proto-stars.
Equilibrium Established
“a state in which opposing forces or influences
are balanced.”
Gravity and Gas Pressure
Nuclear Energy and Gravity
Gravity
Gas Pressure
Birth of a Star
Nuclear Fusion
The process in which a protostar releases thermal energy, photons, supports the star, and stops contraction
When a protostar builds up enough mass to achieve a critical temperature
protostar+heat=nuclear fusion
nuclear fusion-(thermal energy x photons)= star
Second Phase of Life Cycle
Main Sequence Phase
Hydrogen and Helium
Star radiates energy into space
Size of the star
Hydrogen fuel runs out, so the star has to start burning helium in order to maintain stability
Third Phase of Life Cycle
Red Giant
Helium and Hydrogen
Star expands and core contracts due to gravity, and temperature increases until nuclear fusion is possible again (burning helium this time instead of hydrogen)
Nuclear Fusion
Temperature increases and size increased, but core shrinksFinal Phase of Star Life Cycle
The star will either collapse and become a white dwarf and then a black dwarf, or become a supernova,or become a black hole.
Size
When a blue giant gets very hot and bright and collapses then explodes
A supernova is a big explosion of star stuff
Planetary nebula forms when a star can't support itself with fusion in the core
Planetary nebula is a nebula with a shell made from the gas from old red giants