Artifact: Life Cycle of the Stars

1. By Zachary and Alba Artifact: Life Cycle of the Stars

2. Slides 3 through 12 is the life of a small to medium star. This is a picture of a red giant star.

3. Nebula: The first step in a stars life. • Nebula is a big cloud of gas & dust where stars form. • A nebula is considered the birthplace for stars. This is a picture of the horse head nebula.

4. This is a picture of the Helix nebula.

5. Protostar • A protostar is a gaseous cloud of dust, gas and atoms. • Protostars either devolop into a Main Sequence star or a Small Protostar. This is a picture of the pillars of gas in the eagle nebula.

6. Small Protostars • A small protostar is a brown dwarf star. • This star is to small to create enough heat to start fusion. • Since it can’t start fusion it doesn’t shine brightly, so brown dwarf stars are very hard to see in the night sky. These are pictures of a brown dwarf right next to another bigger star.

7. Main Sequence • In a main sequence star the protostar gains enough mass to begin fusion. • The protostar could gain mass from clouds it goes through and other smaller protostars. • All Main Sequence stars fuse hydrogen. • A main sequence star will be a red giant when the Main Sequence runs out of hydrogen.

8. Hydrogen fusion • Hydrogen fusion is when 4 hydrogen nuclei come together to make helium nuclei. • The fusion cycle releases energy inside the core of the sun. • This fusion cycle generates the energy for our sun in our universe.

9. Red Giant • A Red Giant is a Main sequence star that has ran out of hydrogen and begins to fuse helium. When this runs out of fuel, it will turn into a Planetary Nebula. This is a picture of a red giant star.

10. Helium fusion • A kind of nuclear fusion. • Helium fusion is also known as the tri-alpha process.

11. Planetary Nebula • A Planetary Nebula is a red giant that completely stops fusing. • Since the star isn’t producing a pressure outward, the outer layers of the star are driven away. • A Planetary Nebula will turn into a White Dwarf.

12. White Dwarf • A White Dwarf star is a left over core from a star • A White Dwarf may only be the size of the Earth, but it has the mass of half of the sun. • Our sun will become a white dwarf after it runs out of fuel. • White dwarf stars are one of the densest forms of matter.

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14. Black Dwarf • A Black Dwarf is a White Dwarf that cools off over trillions of years until it no longer emits light. • There are no know Black Dwarf stars in the galaxy. Even if there were any we would not be able to see them because they are black. This is a picture of a black dwarf against a star filled back round.

15. Slides 16 through 23 are slides of big stars.

16. Nebula • A nebula for a big star is the exact same as for small to medium stars. • A nebula is a massive cloud of dust and different gasses.

17. Protostar • A protostar for a massive star is the same as a small to medium star. • A protostar is a small star that will turn into a massive main sequence star. This Is a picture of a protostar in the Eagle Nebula.

18. Massive main sequence star • Massive Main Sequence stars fuse hydrogen much faster than small or medium stars. • Since it fuses faster it runs out fuel so fast that it will turn into a Red Supergiant very quickly. This is a picture of a massive main sequence stars layers.

19. Red Supergaint • Massive main sequence star that runs out of hydrogen and begins fusing helium, then carbon, then oxygen etc. • A Red Supergiant star will turn into a Supernova when it runs out of elements that it can fuse. • A Red Supergiant will only live in this phase for a hundred thousand to a million years. This may semm like a long time to us, but it is no time at all in a stars life.

20. Supernova • Fusion stops in the star.Since the star isn’t fusing, gravity takes over and the star collapses. • When the star collapses, there is a gigantic exlposion that rocks the universe. This is a picture of 2 red supergiant stars colliding and producing a very big supernova.

21. Neutron Star • A neutron Star has a super dense core of a star that was left over after the explosion of a supernova. • A neutron star is only 10 to 15 miles in diameter; but have the mass of 1.5-2 times that of the Sun. This is a picture of a neutron.

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23. Black hole • Stars that have masses of 25 to 50 times that of the sun form black holes after a supernova. • The left over core of the star is so dense that is causes gravity to collapse. This is a picture of a black hole.

24. Websites Used!!!!!!! • http://www.historyoftheuniverse.com • http://filter.case.edu/sjr16/advanced/stars_nebula.html • http://en.wikipedia.org/wiki/helix_nebula • http://www.windows.ecar.edu http://www.daviddarling.info/encyclopedia/B/blackdwarf.html

25. More Websites • www.astrophysicsspectator.com/.../stars/MainSequence.html • en.wikipedia.org/wiki/Main_sequence http://www.sciencedaily.com/articles/r/red_supergiant.htm http://aspire.cosmicray.org/labs/star_life/starlife_proto.html http://en.wikipedia.org/wiki/Brown_dwarf

26. Other resources • Mr. Wildeboar’s slide show’s • Our notes