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