Life and Death of a Star 2015 Name Date 1. In the main-sequence, the core is slowly shrinking because A. the mass of the star is slowly increasing B. hydrogen fusing to helium makes the core more dense C. carbon and iron are accumulating in the core 2. In a timeline that shows the sequence of events that occurs during the formation of a star, what happens after the temperature increases in a proto-star? A. nuclear fusion begins B. gravity ceases to act C. rotation begins D. internal temperature drops 3. The heat can be radiated away from a protostar as long as it is A. transparent B. massive C. opaque D. small 4. Molecular clouds are a type of dark nebula. 5. The of a star determines its temperature, luminosity, and diameter. A. composition B. mass C. color D. density E. energy output 6. The more massive a main-sequence star, the faster it burns hydrogen. Therefore it's life is much shorter than averagesized stars. B. FLASE 7. Helium fusion is also known as A. the triple alpha process B. the carbon-12 process C. the quadruple lindy process D. the beryllium-8 process 8. The size of the supernova explosion is directly related to the mass of the star. In other words, the greater the mass, the bigger the explosion. 9. Nuclear fusion begins when temperatures within a protostar reach about: A. 300,000 C B. 10,000,000 C C. 30,000 C D. 150,000,000 C
10. Some nebulae may be the remnant of a supernova explosion. 11. Prior to a supernova event, the heaviest element produced in the core of the most massive stars is A. iron B. neon C. carbon D. oxygen E. helium 12. Immediately prior to a supernova explosion, core material collapses inward at speeds approaching A. 37,500 km/sec B. 100,000 km/sec C. 1,000,000 km/sec 13. The picture below is of the A. Eagle Nebula B. Cocoon Nebula C. Carina Nebula 14. Which correctly lists objects in order of decreasing mass? A. Solar System, Jupiter, Sun, Earth B. Sun, Solar System, Jupiter, Earth C. Solar System, Sun, Jupiter, Earth D. Solar System, Jupiter, Earth, Sun 15. At the precise moment of the supernova event, every element in the periodic table is formed and then ejected outward. 16. A star's core has contracted, meaning that density has increased and the atoms are closer together. If the atoms are closer together, then their atomic collisions should: A. Decrease B. stay the same C. Increase
17. The process of hydrogen fusion (proton-proton chain) releases neutrinos, positrons, and gamma rays as a by-product. 18. Molecular clouds are cold, only about A. 10 K B. 10,000,000 K C. 10,000 K D. 100 K 19. Molecular clouds form just about as many stars as Emission Nebulae and Reflection NEbulae. 20. A white-dwarf star may explode as a type 1a supernova if A. if it enters a nebula B. gets sucked into a black hole C. enough hydrogen gas builds up on its surface D. re-starts fusion in its core 21. All stars, including the Sun, have the following identical composition: A. 25 percent helium; 73 percent hydrogen; and 2 percent oxygen B. 25 percent helium; 73 percent hydrogen; and 2 percent other C. 25 percent hydrogen; 73 percent helium; and 2 percent other D. 25 percent hydrogen; 73 percent helium; and 2 percent oxygen 22. If the force of fusion in the star decreases, then gravity will now dominate hydrostatic equilibrium. This results in an unstable star. What should happen next? A. The core of the star will contract B. the gas presure will puff off the outer layers ofthe star to form a nebula C. the core of the star will explode 23. Pulsars have a strong magnetic field and rotate very rapidly. 24. The density of the interstellar medium makes it almost a complete vacuum. 25. If the solar mass is greater than 20, a star may collapse into a A. white dwarf B. magnetar C. black hole D. pulsar 26. The remnant gasses and dust of a supernova may eventually cool and become a A. dark nebula B. molecular cloud C. a new star D. a new solar system E. all of the above
27. Many star systems in our galaxy are binary star systems. 28. The energy that triggers a supernova event comes FIRST from A. fusion of elements heavier than iron B. collision with another star C. gravitational collapse of the core of a massive star 29. When helium fusion takes over in a star's core, what happens? A. the energy output decreases B. energy output stays the same C. the energy output increases 30. A star that is gravitationally bound to another may be a A. binary B. red giant C. white dwarf D. constellation 31. A type II supernova occurs in stars 9 solar masses or greater. 32. Molecular Clouds are relatively cold compared to other nebula types. 33. Stars more massive than the Sun use up their fuel at a slower rate. 34. The state of matter found in the Sun s interior is plasma. 35. One Dark Nebula can produce thousands of stars. 36. We know black holes exist because A. they are predicted by the theory of relativity B. gravitational lensing C. their effects on nearby stars D. all of the above 37. It takes four hydrogen nuclei to produce one helium-4 nucleus.
38. The sun is in which point of it's life cycle? A. main-sequence B. protostar C. red dwarf D. post-main-sequence E. red giant 39. In the main sequence, as the core slowly contracts, the star gradually grows larger, brighter, and hotter. This is because A. more heat is generated in the core due to increased density B. nuclear fusion is happening at a slightly faster rate C. both of the above D. neither of the above 40. Pulsars are classified according to A. their size B. how they generate energy C. their brightness 41. A magnetar is a type of pulsar that generates energy by A. an extremely strong magnetic field B. rotation C. gravitational contraction 42. Our sun will eventually become a supernova. 43. "High mass stars" eventually become SUPERGIANTS rather than simply red giants. 44. As the core of a main-sequence star depletes its supply of hydrogen, the core begins to A. collapse B. get hotter C. start helium fusion D. A and B E. none of the above 45. Neutron stars are so dense that one teaspoon of its material will weigh as much as A. the sun B. Jupiter C. a car D. Earth
Life and Death of a Star 2015 1. hydrogen fusing to helium makes the core more dense 2. nuclear fusion begins 3. transparent 4. TRUE 5. mass 6. TRUE 7. the triple alpha process 8. TRUE 9. 10,000,000 C 10. TRUE 11. iron 12. 100,000 km/sec 13. Eagle Nebula 14. Solar System, Sun, Jupiter, Earth 15. TRUE 16. Increase 17. TRUE 18. 10 K 19. FALSE 20. enough hydrogen gas builds up on its surface 21. 25 percent helium; 73 percent hydrogen; and 2 percent other 22. The core of the star will contract 23. TRUE 24. TRUE 25. black hole 26. all of the above 27. TRUE 28. gravitational collapse of the core of a massive star 29. the energy output increases 30. binary 31. TRUE 32. TRUE 33. FALSE 34. TRUE 35. TRUE 36. all of the above 37. TRUE 38. main-sequence 39. both of the above 40. how they generate energy 41. an extremely strong magnetic field 42. FALSE 43. TRUE 44. A and B 45. Earth