6. Which star is most like the Sun? -- A
7. Which star is coolest? -- B
8. Which star is intrinsically most luminous? -- B
9. Which star has the smallest radius? -- D
10. Which star is definitely more massive than 1.5 solar masses? -- C
11. Which star has the brightest apparent magnitude? -- E
12. Which star has the weakest gravity at its surface? -- B
13. Which star has the least hydrogen in it? -- D
14. The energy generated in the center of the Sun reaches the surface primarily through
a) the proton-proton chain.
b) collisions between fast-moving protons and slow-moving protons.
c) the mixing of hot material with cold material.
d) collisions between fast-moving electrons and slow-moving electrons.
e) the absorption and re-emission of photons.
15. When a star leaves the main sequence
a) its radius decreases.
b) the size of its core decreases.
c) its luminosity decreases.
d) its temperature increases.
e) its mass increases.
16. Late tonight, if its clear, you can observe Mintaka, the 2nd magnitude star at the top of Orion's belt. In order to determine Mintaka's absolute brightness, you need to measure its
a) mass.
b) parallax.
c) evolutionary state.
d) size.
e) spectral type.
17. Which star may someday turn into a black hole?
a) Procyon, an F main-sequence star.
b) BD+30 3639, the central star of a planetary nebula.
c) Sirius B, a white dwarf.
d) Wolf 359, an M main-sequence star.
e) Spica, an O main-sequence star.
18. A B main-sequence star and an A main-sequence star are in a visual binary system. It follows that
a) the B star must be more evolved than the A star.
b) the B star must have a smaller (brighter) apparent magnitude than the A star.
c) the B star must have a larger Doppler shift than the A star.
d) the B star must have a smaller radius than the A star.
e) the B star must have a smaller mass than the A star.
19. If the parallax of a star is measured to be 0.1 arcseconds, its distance is
a) 0.1 astronomical units.
b) 10 parsecs.
c) 10 astronomical units.
d) 0.1 parsec.
e) 1 parsec.
20. Which property depends on how far a star is away from us?
a) its apparent magnitude
b) its spectral type
c) its absolute magnitude
d) its temperature
e) its mass
21. If the core of a star turns to helium, then
a) the star must be less massive than 1.4 solar masses.
b) the star will very shortly become a supernova.
c) the star will very shortly become a planetary nebula.
d) the star will very shortly become a nova.
e) the star will very shortly move off the main sequence.
22. The elements formed in the center of a star can be expelled into space when
a) the star becomes a planetary nebula.
b) the star turns off the main sequence.
c) the star becomes a nova.
d) the star becomes a white dwarf.
e) the star goes supernova.
23. An astronaut moving at 1/2 the speed of light shines a flashlight. The speed that his light beam travels
a) depends on the color of his flashlight.
b) is exactly the same as it would be if he were standing still.
c) depends on how fast the observer is traveling.
d) depends on the energy of the light.
e) depends on whether the light is produced by a blackbody by an emission line.
24. You go out and take a spectrum of what appears to be a normal G main-sequence star. You see strong absorption at 6556 Angstroms. You want to confirm this, so a few of hours later, you take another spectrum. Once again you see the strong absorption, but this time it's at 6569 Angstroms. Later on, the absorption is back to being at 6556 Angstroms. This behavior can be explained if
a) the star is a spectroscopic binary.
b) the star is evolving off the main sequence.
c) the star is an eclipsing binary.
d) the star is an optical double.
e) the star is a visual binary.
25. Which of the following can escape from inside the event horizon of a black hole?
a) X-rays
b) visible light
c) particles of antimatter
d) particles of matter
e) none of the above
26. If a star in a binary system overflows its Roche Lobe, it will
a) emit x-rays.
b) become hotter.
c) become smaller in size.
d) become more luminous.
e) lose mass.
27. If a star is observed to have strong helium absorption lines, then it must be
a) hot.
b) a binary star.
c) a red giant star.
d) about ready to go supernova.
e) an A-star.
28. Stars spend most of their life
a) as shell burning stars.
b) burning helium to carbon and oxygen in the core.
c) burning hydrogen to helium in their core.
d) as planetary nebulae.
e) as red giant stars.
29. A K main sequence star will never become
a) a core-helium burning star.
b) a G main sequence star.
c) a red giant.
d) a white dwarf.
e) a planetary nebula.
30. Two stars have the same temperature, but the radius of one is twice that of the other. How much brighter is the larger star?
a) 8 times
b) 2 times
c) 4 times
d) 16 times
e) the same, because luminosity depends only on temperature.
31. If the Sun were to collapse into a 1 solar mass black hole
a) the earth would be sucked into the hole (along with the rest of the planets).
b) the earth's orbit would become highly elliptical.
c) the earth would be evaporated by x-rays.
d) nothing would happen to the orbit of the earth.
e) the earth would be ripped apart by the tides.
32. White dwarfs produce energy by
a) fusing helium to carbon and oxygen.
b) gravitational contraction.
c) fusing silicon to iron.
d) fusing hydrogen to helium.
e) white dwarfs don't produce energy -- they have stopped all fusion and are now just cooling off.
33. A black hole is best defined as
a) any object that is smaller than its event horizon.
b) a window to another Universe.
c) the final result of all stellar evolution.
d) a star that sucks all matter into itself.
e) none of the above.
34. Which of these statements about neutron stars is not true?
a) Neutron stars will someday evolve into black holes.
b) Neutron stars are formed in supernova explosions.
c) The surface gravity of a neutron star is greater than that of a white dwarf.
d) Neutron stars can rotate 60 times each minute.
e) Neutron stars are smaller (in size) than Centre County.
35. An M red giant star and an O white dwarf form a binary system. From this information, we know that
a) the system will show strong helium absorption lines.
b) the system will have an accretion disk.
c) the system will appear blue.
d) the system will appear red.
e) the system will appear as a spectroscopic binary.
36. Capella is at a distance of 14 parsecs and has an apparent magnitude of +0.05. Which of the following could reasonably be Capella's absolute magnitude?
a) +0.85
b) +10.5
c) +4.05
d) -10.5
e) -0.7
37. A nova occurs
a) when hydrogen explodes on the surface of a white dwarf.
b) just before a star becomes a planetary nebula.
c) when a high-mass star forms iron in its core.
d) just after a star leaves the main sequence.
e) when a star is becoming a black hole.
38. The copper found in pennies was made
a) in a supernova.
b) in a planetary nebula.
c) in the center of the Earth.
d) in a nova.
e) in the Sun.
39. What holds up the Sun?
a) Radiation pressure
b) Gas pressure
c) Electron degeneracy
d) Neutron degeneracy
e) Nothing -- the Sun is slowly contracting
40. A K-star is observed to emit x-rays. This probably means that
a) the K-star is a red giant.
b) the K-star has just reached the main sequence.
c) the K-star is about ready to go supernova.
d) the K-star is rotating rapidly.
e) the K-star is accreting onto a compact companion star.
41. Which of the properties below can you measure without knowing the star's distance?
a) mass
b) radius
c) absolute magnitude
d) temperature
e) all of the above require knowing the star's distance.
42. When a star becomes red giant, it becomes much brighter because it is
a) moving closer to us.
b) losing its outer envelope.
c) increasing in size.
d) fusing iron in its core.
e) none of the above.
43. The star Procyon has absolute magnitude of 2, while the star Rigel has an absolute magnitude of -2 . If both stars are on the main sequence, the it follows that
a) Rigel is less massive than Procyon.
b) Rigel is smaller than Procyon.
c) Rigel is closer than Procyon.
d) Rigel is fainter than Procyon.
e) Rigel is hotter than Procyon.
44. In a main sequence star, which element is most abundant?
a) oxygen
b) hydrogen
c) iron
d) helium
e) carbon
45. If the Sun had half as much mass
a) it would be larger in size.
b) it would be more luminous.
c) it would be a red giant star.
d) it would be an O star.
e) it would be cooler.
46. Pulsars
a) will eventually collapse to black holes.
b) spin rapidly.
c) are what remains after a planetary nebula.
d) will someday become supernovae.
e) are magnetic main sequence stars.
47. Which object may someday go supernova?
a) an M main-sequence star.
b) an O main-sequence star.
c) the Sun.
d) a planetary nebula.
e) a pulsar.
48. When the Sun's core turns to iron
a) it will go nova.
b) it will become a red giant star.
c) it will go supernova.
d) it will become a white dwarf star.
e) this will not happen -- the Sun's core will never turn to iron.
49. The Sun will destroy the Earth when
a) it becomes a planetary nebula.
b) it becomes a red giant star.
c) when it starts to burn helium in its core.
d) it becomes a binary star.
e) it goes nova.
50. Observations of binary stars are useful for determining stellar
a) masses
b) temperatures
c) luminosities
d) spectral types
e) distances