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