1. LIFE CYCLE OF STARS

2. Nebulae – Life Stage of stars • Nebulae are clouds of gas and dust within which stars are “born”. • 1.) Diffuse Nebula are nebular clouds that both emit light (from stars forming within) and reflect lightfrom nearby stars, so light from these clouds can be seen.

3. NEBULAE • 2.) Dark Nebula are dense clouds of gas and dust that are dark and block the view of light of diffuse nebula and stars that they are in front of.

4. Protostars - Life Stage of stars • As particles of gas continue to collide, they form clumps of matter. These clumps get hotter and hotter and when a distinct, swirling mass forms, an unstable “protostar” is formed. A protostar does not shine yet.

5. Young star - Life Stage of stars • When nuclear fusion takes place in the core of a protostar, the star becomes stable and begins to shine. This stable state is often referred to as the “young star” stage.

6. Red Giants and Supernovas – Death Stage of Stars • Stars go through a “death” stage when their hydrogen is depleted (runs out) through the process of nuclear fusion. • Stars with low to average size and mass will eventually become unstable and their cores will contract, while their outer atmospheres (coronas) expand to several times their previous size in a Red Giant phase. Our sun will go through this phase in about 5 billion years!

7. Red Giants and Supernovas – Death Stage of Stars • A low to average size and mass star will then become a small, dense star called a white dwarf star. When it loses energy, it becomes a cold, black object in space called a black dwarf star.

8. Red Giants and Supernovas – Death Stage of Stars • Stars with a high mass also become very unstable when they begin to die, but they will go through a Supernova explosion after a Red Giant phase. This can be seen as a brilliant flash of light in the night sky that can last for days.

9. Red Giants and Supernovas – Death Stage of Stars • The remains of a supernova explosion can be very dense object in space such as Neutron (Pulsar) Stars which emit pulses of radiation as they spin. • If the star was massive enough to begin with, a Black Hole.

10. Life cycle of stars http://www.youtube.com/watch?v=PM9CQDlQI0A