Life Cycle of Stars LT: SWBAT identify the basic timeline of star lifecycle AND describe the processes that produce stellar energy and elements. Opener: From your observations how are stars different from planets? https://www.youtube.com/watch?v=TfkZ_GtS5wk

Formation How does a proto-star form? Why doesn’t this process create planets? Why does the proto-star become hot? Stop @ 18 seconds

Main sequence Star How do fusion reactions produce elements greater than Hydrogen? What would happen if the force of fusion pushing out was unbalanced with gravity in a newly formed star? The proton-proton fusion cycle is shown to the right. What are it’s products? Stop @ 37 seconds Proton-Proton Cycle: Two H nuclei collide to form deuterium-fusion is accompanied by enough energy to convert one of the protons to a neutron, an additional proton combines with deuterium forming He-3 (gamma radiation). Two He-3 particles fuse and eject two protons resulting in a “normal” helium atom.

Death of a Star What causes the death of a star? Describe the two possible pathways of a dying star. (Really push for productive fusion reactions.)

Sun-Earth Interactions What interactions occur between the Sun & Earth? (Hint: what particles do we get from the sun) How does the Earth rely on energy from the sun? What will happen to Earth when the Sun enters its red giant phase? @ 55

Where do Chemical Elements Come from? Why do much larger star than our Sun stop fusing elements at iron? How are these heavier elements formed in the super nova? @ the end

Details about the Sun Age ~ 5-6 billion years Core temperature ~15 million Kelvin 73% Hydrogen 24.8% Helium The remaining elements include: oxygen, carbon, neon, nitrogen, magnesium, iron, and silicon Fun Fact: a pinhead at the temperature of the sun (15 million Kelvin) would radiate enough heat to kill a man 100 miles away!