Download 1. 1st Step

III. Stellar Evolution
You’re a Superstar!
1. 1st Step:
a. Stars form from nebulas (cloud of dust &
gas)
2. 2nd Step:
a. As nebula contracts, a small star is formed
called a protostar
b. Eventually, the protostar will begin
nuclear fusion (elements coming together)
3. 3rd Step:
a. Star joins the main sequence
1.) 90% of stars spend life here
Life Cycle of Stars
4. 4th Step:
a. What stars end up as depend on mass
b. Low mass = red giant (massive star, a
lot of fusion)
c. High mass = supergiant (largest known
star, burn out fast)
5. Death of Stars:
a. Low and Medium mass stars
• Planetary nebula --------- white dwarf (dense,
faint star)------ black dwarf (dead star)
b. High mass stars
• Supernova (exploding star) --------- neutron
star(remains of star) or black hole (massive
gravity absorbs everything near it)
Relative Size of Stars to Planets
Earth Science Bellringer
• Get out your comp. books!
Star Life Cycle Diagram
Using pg. 764-765 draw a DETAILED &
LABELED diagram of the star life cycle in
your composition notebook.
Red textbook
Star Life Cycle Questions:
1.
2.
3.
4.
5.
6.
7.
What is a nebula?
How does a star form from a nebula?
How is a protostar different from a star?
What factors determine how long a star lives?
What is the ultimate fate of our sun?
What type of stars may become black holes?
Describe the difference between a white dwarf
and a black dwarf.
8. Describe the two alternatives for a supernova.