1. Life Cycle of a Star Based on Mass of Star

2. All Stars – Stage 1-Nebula Gravity main force, pulls cloud INWARD. Temperature = INCREASES Gravity based on MASS OF CLOUD.

3. Orion’s Nebula

4. All Stars – Stage 1 - PROTOSTAR Size DECREASES Mass becomes more DENSE Temperature hot enough to give off light.

5. Protostar

6. All Stars – Stage 2 – Main Sequence Nuclear Fusion begins in core. Heat pushes OUTWARD Star becomes STABLE Now a MAIN SEQUENCE STAR

7. Main Sequence star Our Sun

8. Nuclear Fusion Hydrogen fuses into Helium in the Core. 4 H  1 He Creates great heat! E = mc 2

9. Red Giant

10. Medium Mass Star (Sun)-Stage 3 Red Giant – Runs out of hydrogen fuel – Fusion occurs in outer shell causing expansion – Outward pressure GREATER than inward pressure. – Sun will expand out to Mars. – Cools and turns Red.

11. Medium Mass Star – Final Stage White Dwarf = Hot but Dim – Red Giant core collapses Inward pressure GREATER than outward pressure Outer shell escapes into space = Planetary Nebula

12. White Dwarf with Planetary Nebula Foofing 

13. High Mass Star Stages First stages the same but more MASSIVE! – Nebula – Protostar – Main sequence

14. H-R Diagram Where would High-Mass main sequence stars be?

15. High Mass Star Stages Super Giant – Higher heat and mass allows fusion of heavier elements. H  He  C  O  Fe – Outward pressure GREATER than inward pressure – Expands, runs out of fuel and cools = turns Red

16. Super Giant

17. High Mass Star – The End Super Giant runs out of fuel = Core collapses – Inward pressure GREATER than outward pressure Core collapse triggers EXPLOSION! – Explosion = SUPER NOVA

18. Super Nova

19. High Mass Star – The End Core continues to collapse – Gravitational force HUGE! – Turns into a NEUTRON STAR Gives off pulsing radio waves (called Pulsar)

20. High Mass Star – The End Black Hole – If massive enough: Continues to collapse into a Black Hole Inward pressure GREATER than outward pressure – Gravity so great, light cannot travel fast enough to escape them. – Detected by X-rays emitted by things being pulled in.

21. Black Hole

22. Life Expectancy of a Star Low Mass Star – 100 Billion years Medium Mass Star (our Sun) – 10 Billion years High Mass Star – 10 Million years  The Mass of a star determines the length of it’s life.  More Mass = Higher energy used = shorter life.

23. Solar Nebula Theory A.NebulaNebula B.Main sequence – accretion disk formedMain sequence – accretion disk formed C.Collision of particles formed clumpsCollision of particles formed clumps D.Clumps formed asteroidsClumps formed asteroids E.Asteroids became planetsAsteroids became planets https://www.youtube.com/watch?v=V W9FJb1HkDU (2:04 min) https://www.youtube.com/watch?v=V W9FJb1HkDU https://www.youtube.com/watch?v=PL3YNQK 960Yhttps://www.youtube.com/watch?v=PL3YNQK 960Y (3:05 min)