1. Stars begin as gas and dust called a nebula.
Lives of Stars
Stars begin as gas and dust called a nebula.
Gravity pulls the gas and dust in and fusion begins. This forms a Protostar or ‘new star’

2. Protostar

3. Lifetimes of Stars A star’s life depends on its mass.
Stars smaller than the sun live up to 200 billion years.
Medium sized stars like the sun live around 10 billion years.
Stars 15 times more massive than the sun live about 10 million years.

4. Star Life Cycle Nebula Protostar
Main Sequence: 90% of stars. Hydrogen continues to burn and fuse to make helium.

5. MAIN SEQUENCE

6. Giant/Super Giant: The star begins to run out of fuel. The star expands.
Supernova: Massive stars can blow up to an enormous size.

7. mass
RED GIANT

8. Small and Medium Stars These become giants and then
White Dwarfs: blue-white core of a star that is left behind.
These have no fuel, but glow faintly from left over energy.
When a white dwarf burns out, it is dead. Then it is a Black Dwarf.

9. fusion
WHITE DWARF
PULSAR

10. Super Giants:
When a Super Giant explodes into a supernova, it can become 2 things:
A. Neutron Star: Smaller and more dense than a white dwarf. They have 3 times as much mass as the sun, but are about the size of Houston!
Black Hole: This object is so dense, not even light can escape the gravity field.

11. SUPERNOVA
explosion
Super Nova

12. :
BLACK HOLE

13. White Dwarf Supernova Black Dwarf Nebula  Protostar  Main Sequence 
Giant or Supergiant 
White Dwarf Supernova
Neutron Star
Black Dwarf OR
Black Hole

15. Binary Star Systems Stars that revolve around each other.
Sometimes this causes stars to appear as if they are blinking

16. Let’s Review!
1. All stars begin as gas and dust called
Protostar
Nebula
White dwarf

17. 2. Most stars are in this stage
a. Protostar
b. White Dwarf
c. Main Sequence

18. 3. The life of a star depends on its
a. Color
b. Place in the universe
c. Mass

19. 4. If the star is super massive, it will live longer.
a. True
b. False

20. 5. Low mass stars will become black holes
a. True
b. False

21. 6. An object so dense, not even light can escape.
a. Supernova
b. Main Sequence
c. Black Hole
d. Nebula

22. 7. A new star where fusion begins.
a. Protostar
b. Neutron Star
c. Main Sequence

23. Today’s Assignment and Homework:
Complete pages
296, 299, 301,302