2. Topic: The Life Cycle of Stars PSSA: 3.4.7.D/S8.D.3.1

3. Objective: TLW identify the major events in the life cycle of main sequence and massive stars.

4. MI #1: Nebulae Nebulae (or nebulas) are large clouds of dust and gas in space. Hydrogen in the nebula is converted to helium through nuclear fusion eventually generating a star.

6. MI #2: Main Sequence Stars This is the longest part of a star’s life cycle. Eventually main sequence stars use most of their hydrogen and begin to cool.

7. MI #3: Main Sequence Stars (Part 2) Giants and supergiants form when main sequence stars expand after cooling. When a giant star finally collapses, it forms a white dwarf. White dwarf stars burn hot, but do not generate additional energy through fusion.

9. MI #4: Supernovas A supernova is a giant explosion of a massive star that occurs when it collapses and throws its outer layers into space.

12. MI #5: Neutron Stars Neutron stars are the collapsed core of a supernova. There is so much gravity that the electrons and protons are smashed together to form neutrons. If the neutron star is spinning it is called a pulsar.

13. MI #6: Black Holes Black holes form if the mass of the center of a collapsed star is more than three times the mass of the sun. Black holes are so massive that their gravity prevents light from escaping.

15. So What…? Real Life Application Understanding the life cycle of a star helps us understand why there are different types of stars, as well as why supernovas and black holes form.