Star Life Cycle

1. From birth… to death… Star Life Cycle

2. Nebula • A huge cloud of dust and gas (mostly hydrogen) pulled together by gravity • Called the “birthplace of a star” • Theory is that the dust came from the explosions of other stars

3. Nebulae Examples…

4. Protostar • Gravity causes the particles of gas and dust to move together • Temperature and pressure increase and the cloud begins to spin

5. Star • The protostar continues to contract due to gravity • Temperature and pressure continue to increase • When temperature reaches 10 million degrees Celsius, nuclear fusion begins

6. Nuclear Fusion • At temperatures of 10 to 15 million degrees Celsius, nuclear fusion occurs in stars • Hydrogen are converted into one helium plus a lot of energy!

7. Main Sequence Stars(type of star depends upon mass)

8. Main Sequence Stars

9. Star Death • Death is determined by mass. When the last of helium atoms in the core are fused into carbon atoms, the star begins to die. • A sun-sized star will first expand to a red giant, then collapse on itself to become a white dwarf.

10. Massive Star Death • Energy is released in a powerful explosion called a supernova • It then becomes a neutron star. No nuclear fusion is taking place to support the core, so it is swallowed by its own gravity.

11. Black Holes Only a very massive star can become a black hole, which is not visible and is so dense nothing can escape.

12. Some media • http://science.discovery.com/video-topics/space-videos/supermassive-black-holes-the-black-hole.htm • http://www.space.com/15421-black-holes-facts-formation-discovery-sdcmp.html

13. The Visible Sun