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Astronomy Semester 1 Exam Study Guide
Fall 2013
• These are going to be the questions on the exam, with very few modifications. The question numbers won’t
change and the wording won’t change, but problems that marked with a ❆ will have a detail changed on the
exam. All questions will be multiple choice. Some of the question statements might not make complete sense
here on the study guide, but on the exam the list of responses will make the question clear.
• You will need your Messier list, planisphere, planet graph and the SFA Star Chart. You will also need a calculator.
• You may prepare a handwritten note sheet, 8½” × 11”, both sides. No photocopies. You will submit your note
sheet with the exam. The same reference section provided with this study guide will also be provided with
the exam.
UNIT 1 — Overview/Sense of Scale/History of Astronomy — Ch. 1, 4, and bits of 5
1.
Indicate the proper ranking of these objects from smallest to largest: Cluster of galaxies, Galaxy, Planet, Star,
Solar System, Supercluster.
2.
A light year is …
3.
The Local Group is …
4.
Which calendar (Julian or Gregorian) are we on now?
5.
Based on our current calendar system, which of the following years will not be a leap year?
6.
Which of the following people did not accept a heliocentric model for the Universe?
7.
Kepler’s first law states that …
For questions 8-11, match the person to the following theories, discoveries or observations:
8.
• Jupiter has moons
9.
• general relativity
10. • planets sweep out equal areas in equal times
11. • first to systematically study the night sky with a telescope.
12. The observation of the phases of Venus was strong evidence against which ancient belief?
13. How did Mercury’s orbit differ from the Newtonian prediction, and how did this difference ultimately provide support for General Relativity?
UNIT 2 — Celestial Motions — Ch. 2 and 3
14. The celestial equator is …
15. A first quarter moon rises at what time? ❆
16. What phase must the moon be in for a solar eclipse?
17. What does the α mean in the name α-Lyra?
18. A star is listed in a catalog to be 8th magnitude. Could you see this without a telescope?
19. In this picture, what phase is the moon in?
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20. Which of these is a correct description of the summer solstice?
21. If you are at the equator and watching the Sun rise, you’ll see …
22. An equinox is …
23. Astronomers say that the Moon is tidally locked to the Earth. What does tidally locked mean?
UNIT 3 — Stargazing Aids — No sections in the textbook: Notes only
24. What planet is going through opposition in early April of 2014? ❆
25. What is the Right Ascension of M57? ❆
26. Based on this data concerning satellite positions, we can tell that which satellite will be highest above the
horizon?
27. The Messier List was generated by an astronomer who was interested in studying what kind of object?
28. Altitude and Azimuth are useful because …
29. Celestial coordinates (RA and Dec) are useful because …
30. Find the star whose coordinates are RA=4h35m and Dec=16°. ❆
31. What is zodiacal light?
32. Describe the challenges in seeing a very young moon.
33. Describe a planetary “alignment” and two common misconceptions about such alignments.
UNIT 4 — Light and Telescopes — Ch. 6
34. Order the following types of light in terms of increasing energy: blue visible, gamma rays, green visible, infrared, microwaves, radio waves, red visible, ultraviolet, x-rays
35. A telescope designed to detect which of the following types of light must be used completely above Earth’s
atmosphere?
36. The technique called ______________ uses a thin flexible primary mirror and computer controlled actuators
under the mirror to control its shape of in order to correct for distortions caused by a variety of things including the mirror’s weight and position.
37. The technique called ______________ uses a high speed computer to monitor atmospheric distortion (often
with a laser generated false star) and adjust the optics of a telescope to partially compensate for the atmosphere.
38. The technique called ______________ uses multiple dishes to collect light and combines that light to produce
an image with better angular resolution, as though it were collect by a single, larger telescope
39. Astronomers build telescopes on tops of mountains because
40. To increase the light gathering power of a telescope you need to …
41. Suppose a new research telescope boasts resolving power better than any space based telescope. Should we
continue to make space based telescopes?
42. The VLT is a
(1)
telescope in
(2)
. The VLT makes use of
43. The VLA is a
(1)
telescope in
(2)
. The VLA makes use of
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(3)
(3)
to improve its imagery.
to improve its imagery.
44. What is averted vision and what do you use it for?
For questions 45-49. While out on a stargazing trip using a telescope an observer might encounter the following
problems. Match each problems with the most appropriate solution.
45. • I’m pointed directly at the right spot, but I don’t see my faint object
46. • I have a big enough telescope, but my faint object blends in with the grey sky.
47. • My object seems too small. I want more magnification.
48. • My object seems so big it doesn’t fit in my field of view. I want to see more of it.
49. • My object seems all blurry, wavy or fuzzy.
UNIT 5 — Analyzing Light — Ch. 7
50. A star is measured to have a B magnitude of 6.3 and a V magnitude of 6.0. Find its temperature. ❆ (See Reference Item 2.)
51. Stars of what temperature should be expected to produce a peak wavelength of 320 nm? ❆ (See Reference
Item 1.)
52. Alberio is a famous binary system consisting of two stars, one noticeably blue and the other noticeably orange. What do these different colors tell us about these star?
53. Based on the given stellar spectra references, what would be the spectral type of this star? (See Reference
Item 6.)
54. A star’s L line is measured at 102.3 nm, even though we somehow know it was 102.6 nm when released from
the star. Is the star moving towards or away from us? ❆
β
55. How is it possible to know that we know the original wavelength of that particular light was 102.6 nm?
56. Blackbody radiation produces a I spectrum from a star’s
produce a III spectrum from a star’s IV .
II
while electrons jumping up in energy levels
UNIT 6 — Family of Stars — Ch. 9
57. Annie J. Cannon classified thousands of stars based on their spectral lines. What is the primary physical characteristic that spectral lines tell us about a star?
58. How can certain stars be much hotter than the sun even though they are much dimmer than the sun?
59. A star has a surface temperature of 6,000 K and a luminosity of 100 L⨀. Which of these is a best estimate of its
radius? ❆ (See Reference Item 3.)
60. A star at a distance of 67 pc will have a parallax angle of what? ❆ (See Reference Item 1.)
61. How far is 67 pc in light years? ❆ (See Reference Item 1.)
62. A star is of spectral type F1. Estimate its surface temperature. ❆ (See Reference Item 3.)
For questions 63-67, estimate the following: ❆ (See Reference Item 3.)
63. • The surface temperature of Vega ❆ (See Reference Item 3.)
64. • The radius of Wolf 486 ❆ (See Reference Item 3.)
65. • The luminosity of Capella A ❆ (See Reference Item 3.)
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66. • The absolute magnitude of Aldebaran B ❆ (See Reference Item 3.)
67. • The spectral type of Rigel B ❆ (See Reference Item 3.)
68. A Bright Giant star has a temperature of 10,000 K. Which of these is a best estimate of its luminosity? ❆ (See
Reference Item 5.)
69. A binary star system might have an orbital inclination best described as “edge-on” while another might be
considered “face on.” Which of these two arrangements is necessary for an eclipsing binary?
70. A star is measured to have a distance of 160pc and an apparent magnitude of 3.0. What is its absolute magnitude? ❆ (See Reference Item 4.)
71. Luminosity class can be identified by careful analysis of a star’s what?
72. Why are red dwarfs, even though they are the most common kind of star, not the most commonly seen type
of star in the sky?
UNIT 7 — The Lives and Structure of Stars — Bits of Chapters 8, 10-14
73. The interstellar medium is what percent of the mass of the whole galaxy? (A spiral galaxy, like the Milky
Way.)
74. You are looking at an astronomical poster and someone says, “Ooo! That’s a pretty red blobby thing.” Most
likely this is …
75. Astronomers find radio waves with a wavelength of 21-cm line useful for studying …
76. What does hydrostatic equilibrium say about the pressure in the layers of a star? It says that the _____1_____
in each layer must balance the _____2_____ of all higher layers, causing the temperature and _____1_____ to
increase from the surface to the center.
77. Which of these stars will stay on the main sequence for the shortest amount of time?
78. Which of these stars will stay on the main sequence for the longest amount of time?
79. Correctly match star mass, energy transport and nuclear reactions:
• high mass / medium mass / low mass
• radiative center, convective outer layer / convective center, radiative outer layer / convective throughout
• proton-proton chain / CNO cycle
80. What happens to a main sequence star when it runs out of hydrogen fuel in its core?
81. A planetary nebula is …
82. How is a white dwarf formed?
83. Why are bright blue stars an indicator of recent star formation?
84. Why are star clusters so useful in testing theories of stellar evolution?
85. What is the proper order of the following objects in terms of increasing size? brown dwarf, G-type main sequence star, M-type main sequence star, neutron star, O-type main sequence star, red giant, supergiant, white
dwarf.
86. Theory says that stars in the range of 0.08 to 0.25 solar masses will eventually form a helium white dwarf star.
Why are no helium white dwarfs observed in our galaxy?
87. One night you look into the sky and you see a star where you’re sure there was no visible star ever before.
Which TWO of these is a possible explanation?
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88. If a white dwarf is in a binary, what can happen to it and what does it become?
89. A neutron star is expected to spin rapidly because
90. In a survey of pulsars in binary systems, it is found that none of the pulsars has a mass greater than 3 solar
masses. This is because …
91. If the Sun were replaced by a 1-solar-mass black hole, how would the Earth be affected?
92. A massive star becomes a supernova when it …
93. Nuclear fusion in the Sun will create which element?
For Questions 94 through 97, match the provided nucleosynthesis process with the element(s) that it produces.
94. • Primordial (Big Bang)
95. • Main Sequence stellar nucleosynthesis
96. • Post main sequence stellar nucleosynthesis
97. • Supernova
98. According to the Chart of Stellar Evolution (see Reference Item 7), planetary nebula can form from main sequence stars of mass …
UNIT 8 — Galaxies and Cosmology — Bits of Chapters 15-18
100. What makes Cephied Variables very useful for measuring distances?
101. Contrast the motion of the disk stars and that of the halo stars.
102. What’s most likely the formation process of large elliptical galaxies? How does this explain their amount of
interstellar medium?
103. Why couldn’t spiral arms be physically connected structures? What would happen to them?
104. What property of dark matter reveals its existence?
105. After two galaxies merge and settle down into one galaxy, would you expect the resulting galaxy to have
more or less ISM than the original galaxies?
106. Explain the origin of the name “quasar.”
107. The scientist who first found evidence that the universe was expanding was looking for what kind of data?
108. What role do Type Ia supernovae play in measurements of cosmological expansion?
109. What evidence do we have that the universe is expanding? that it began with a big bang?
110. What’s the origin of the Cosmic Background Radiation?
111. How can the Observable Universe be finite but the whole Universe be infinite?
112. WMAP is a satellite dedicated to studying what?
113. Dark matter helps explain which of these observations?
114. Dark energy helps explain which of these observations?
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