1. Lives of Stars Chapter 17 Section 4 Pages 583-589 Chapter 17 Section 4 Pages 583-589

2. Life Cycle of Stars

3. 1. Nebula- A star nursery (gases and dust) –Gravity pulls gas and dust together. 2. Protostar (earliest) –Star is born when nuclear fusion starts. (combining hydrogen into Helium. Releases large amounts of energy. Birth of a Star

4. Determined By Mass! 1.Large Stars- Short lives (10 million) 2.Medium Stars- (10 billion) 1.The sun 4.6 Billion Years old 3.Small Stars- Long Lives (200 billion) Life Time of Stars

5. 1.Occurs when a star begins to run out of fuel. 2.All stars become a giant or a super giant depending on their mass. 3.The final fate of a star is determined by mass. Death of Stars

6. Small Medium Stars Were once red giants that lost their atmosphere A glowing white core remains –About the size of Earth –1 million times denser than the sun When it stops glowing, it’s dead, becomes a black dwarf. White Dwarfs

7. When a giant or supergiant star suddenly explodes. Must be a massive star. Gases expelled can become a new star. Super Nova

8. Left by a Supernova. When a giant or super giant star explodes. Smaller than white dwarfs Extremely Dense Pulsar- spinning neutron stars that give off radio waves. Neutron Stars

9. Occurs after the most massive stars explode. Gravity PULLS gasses into a small place. Gravity becomes so great that nothing not even light can escape. Black Hole

10. Very bright objects, but far away. 12 billion light years Very distant galaxies with very massive black holes in the center. The gases around the black hole heat up and shine brightly. Quasars