STELLAR EVOLUTION WEBQUEST Go to the Life & Death of Stars website (address is just below.) Answer the following questions as you read the information on this website. BE CAREFUL TO TYPE IN THE WEBSITES ACCURATELY! http://map.gsfc.nasa.gov/m_uni/uni_101stars.html 1. Where are stars born? Nebulas, molecular clouds of gas and dust 2. What do they form when the nebula collapses? Protostars 3. What is the initial source of energy for the collapsing star? Gravitational Energy 4. Once the central core becomes hot enough, what is the core doing to become a main sequence star? Fuses hydrogen into helium Main Sequence Stars 5. What is a main sequence star? Fuse hydrogen atoms into helium atoms to make energy 6. How many times more luminous are stars that are 10 times more massive than our Sun? Over 1000 times more luminous 7. What color are more massive stars? Blue 8. Do high mass stars exhaust their supply of hydrogen faster or slower than less massive stars? Faster 9. What happens to a star as it exhausts it supply of hydrogen? Becomes redder, larger and more luminous. Becomes a giant star. Death of an “Ordinary Star 10. Nuclear fusion no longer goes on in the core. Where is it happening? Hydrogen burning continues in a shell around the core. 11. At that time, what stage will the Sun become? Red giant 12. What will happen to Earth? The atmosphere of the red giant sun will envelop the Earth in fire 13. What happens to the core? Why? Core of the star collapses due to the pull of gravity. 14. What is “burning” now in the core? Helium is fusing into carbon. 15. What stage will the Sun become next? Planetary nebula STELLAR EVOLUTION WEBQUEST 16. What happens to the “envelope” of the Sun? Outer envelop will extend out to Jupiter, but then will disperse. 17. What is left behind? Core of the tar. 18. What eventually becomes of the core of our Sun? Will become a white dwarf (eventually a black dwarf) Death of a Massive Star 19. What happens when a massive star exhausts the helium in its core? Continues “burning” (fusing) atoms in its core. 20. What elements does it start to “burn” after helium is gone? (Name them all in order) Helium to carbon, carbon to oxygen, neon, silicon, sulfur and iron. 21. What happens to the iron core? Does not fuse into any other element. The iron core collapses due to gravity. Eventually can’t collapse any more and the matter “bounces” off the core in a supernova explosion. 22. How bright is a supernova? Brighter than an entire galaxy of stars. 23. How much mass does a star need to form a neutron star? At least 10 times the mass of the sun. 24. What happens to stars that are larger than the ones that form neutron stars? Forms a black hole. Click on White Dwarfs at the bottom of the page-http://chandra.harvard.edu/xray_sources/white_dwarfs.html Be sure to read pages 1 & 2 (at the bottom) in order to find the answers to these questions. 25. When will the Sun become a Red Giant (look at the illustrations & notice the relative sizes of the Sun now, as a Red Giant, & Earth)? 5 billion years from now 26. Again, look at the next illustration and note the relative sizes. When will the sun become a White Dwarf? 6 billion years from now 27. Finish this statement: “In the white dwarf state, all the material contain in the star… will be packed into a volume __1 millionth_________________________ the size of the original star. An object the size of an ___olive___________ made of this material would have the same mass as an ____automobile_________________ !” Go back to Life & Death of Stars website. http://map.gsfc.nasa.gov/m_uni/uni_101stars.html Click on Neutron Stars http://map.gsfc.nasa.gov/m_uni/uni_101stars.html STELLAR EVOLUTION WEBQUEST Be sure to read pages 1 – 3 (you can skip pp. 4, 5, & 6) 28. What happens to the atoms in a neutron star? Atoms are crushed completely and the electrons are jammed inside the protons to create a star that is only made up of neutrons. 29. What would happen to your spacecraft if you could travel to a neutron star? Why? Intense gravitational field would pull it to pieces. 30. If the gravitational force didn’t do you in, what else would? Intense magnetic field would squeeze the atoms into various shapes. 31. What is a pulsar? Rotation could cause a great electric field with high voltages to form. These high voltages can produce beams of pulsing radiation. Go back to Life & Death of Stars website http://map.gsfc.nasa.gov/m_uni/uni_101stars.html Click on Black Holes http://chandra.harvard.edu/xray_sources/blackholes.html Then click on Stellar (Be sure to read pages 1 – 3 to answer the questions.) 32. How much mass is required for a stellar black hole to form? At least 3 times the mass of the Sun. 33. Place the cursor over “black hole” and answer the question: What is a black hole? dense, compact object whose gravitational pull is so strong that - within a certain distance of it - nothing can escape, not even light 34. What happens to anything that passes beyond the event horizon? Will be crushed. 35. About how big (radius) is the event horizon of a star with a mass of 10 suns? 30 km (not that big) 36. How do astronomers see a black hole? Can’t really see. Infer that it is there by implying that large amount of matter is in a small space due to how other matter interacts with it. 37. How do black holes grow? The mass of a black hole will increase when matter falls into it. Go back to Life & Death of Stars http://map.gsfc.nasa.gov/m_uni/uni_101stars.html Click on Supernovae http://chandra.harvard.edu/xray_sources/supernovas.html 38. How often does a Supernova happen in our galaxy? About once every 50 years. STELLAR EVOLUTION WEBQUEST Click on the Chandra Image of SN 1006 and read that page and answer this last question. 39. In what year did the “new star” suddenly appear & what object did it outshine? 1006 AD. Outshined the planet Venus.
