Download Sample Exam for 3 rd Astro Exam

Dr. Fred Jaquin
Astronomy , SCI 103
Unit 4 Test: The Milky Way and Other Galaxies
Record all answers on the Scantron sheets provided. Use a number two pencil.
1. Galaxy #1
A. E0
NGC 1300
B. E5
C. Sc
D. SBc
E. SBa
2. Galaxy #2
NGC 1433
A. SBb
B. E1
C. Sc
D. Irr
E. Sa
3. Galaxy #3
A. E0
NGC 3031
B. Irr
C. SBb
D. Sb
E. E3
4. Galaxy #4
A. E4
NGC 3034
B. E0
C. Sc
D. Irr
E. Sa
5. Galaxy #5
NGC 4472
A. SBc
B. E0
C. Sc
D. Sa
E. E3
6. Galaxy #6
A. E0
NGC 4565
B. E5
C. Sb
D. Irr
E. SBa
7. Galaxy #7
A. Sa
NGC 4594
B. E5
C. Irr
D. E0
E. SBa
7. Galaxy #8
A. E0
NGC 4697
B. E5
C. Irr
D. S0
E. SBa
9. Galaxy #9
A. Sc
NGC 5457
B. E5
C. Irr
D. Sa
E. SBa
10. Galaxy #10 NGC 5907
A. Sc
B. E5
C. Irr
D. Sa
E. Sba
11. The disk of our Milky Way galaxy is about how large in diameter?
A. 1,000 parsecs
D. 50,000 parsecs
B. 10,000 parsecs
E. 100,000 parsecs
C. 36,000 parsecs
12. Which of the numbers below represents the thickness of the disk of the Milky Way?
A. 250 parsecs
D. 36,000 light years
B. 1,000 light years
E. 36,000 parsecs
C. 1,000 parsecs
13. What is the diameter of the halo of our Milky Way galaxy?
A. 14 parsecs
B. 1,000 parsecs
C. 10,000 parsecs
D. 50,000 parsecs
E. 100,000 parsecs
14. Approximately how far is the Sun from the center of the Milky Way?
A. 36,000 parsecs
D. 250 parsecs
B. 10,000 parsecs
E. 14 parsecs
C. 1,000 parsecs
15. Where is the galactic gas layer located?
A. In the galactic halo.
B. In the galactic nuclear bulge
C. Beyond the Sun above and below the galactic mid-plane
D. Perpendicular to the galactic plane.
E. In the galactic mid-plane
16. True or false: The Sun is located within the galactic gas layer of the Milky Way
A. True
B. False
C. I have no @#%&*! idea
17. Which statement below best describes the nuclear bulge of spiral galaxies?
A. The nuclear bulge is nearly spherically shaped with an average density of stars.
B. The nuclear bulge is nearly spherically shaped with a below average density of stars.
C. The nuclear bulge is nearly spherically shaped with an above average density of stars.
D. The nuclear bulge is disk-shaped with black holes around its periphery.
E. Spiral galaxies do not have nuclear bulges. Only Elliptical galaxies have nuclear bulges.
18. RR Lyra stars are a useful star for estimating astronomical distances because
A. All RR Lyra stars are the same distance from the Sun.
B. All RR Lyra stars are the same luminosity, about 100 solar luminosities.
C. All RR Lyra stars are located in the bulge of our galaxy.
D. RR Lyra stars can be seen at distances of 200 Mpc.
19. In spiral galaxies, globular clusters are distributed
A. in the spiral arms of the disk and they orbit the center of the galaxy in circular orbits.
B. in between spiral arms of the disk and they orbit the center of the galaxy in circular orbits.
C. in the halo of the galaxy and they have randomly oriented elliptical orbits around the center of the
galaxy.
D. in the halo of the galaxy and they are carried around the halo in circular motion as the halo rotates
like a solid body.
E. There are no globular clusters in spiral galaxies. They are found only in elliptical galaxies.
20. What is the general shape of the aggregation of stars we live in?
A. A thin disk of stars where we are in the center of the distribution.
B. A large spherical arrangement of stars that is denser towards the center.
C. A thin disk of stars surrounding a central bulge where we are about 2/3's the way out
from the center.
D. An irregular arrangement of stars, dust, and gas with no central condensation where we are near the
center.
E. A large ellipsoidal arrangement of stars.
21. The spiral arms of our galaxy are uniquely populated by which of the objects listed below?
A. Globular clusters
C. Early spectral types like O and B stars
B. Late spectral type=s like G, K, and M
D. Planetary nebula and giant stars
E. Population II stars
stars
22. Is there any limitation on our view of the disk of the Milky Way using visual observations?
A. No
B. Yes - Interstellar dust limits our view within the disk to 100 light years.
C. Yes - Interstellar dust limits our view within the disk to 1,000 light years.
D. Yes - Interstellar dust limits our view within the disk to 10,000 light years.
E. Yes - Interstellar dust limits our view within the disk to 100,000 light years.
23. How is the dust distributed within the Milky Way?
A. It is uniformly distributed in a spherical halo, centered upon the galactic center.
B. It is mostly concentrated in the galactic nucleus.
C. It is concentrated only in the spiral arms.
D. It is concentrated in the mid-plane of the galactic disk along with the spiral arms.
E. It is not distributed in our galaxy since spiral galaxies do not contain dust.
24. Of the objects listed below, which do NOT take part in the general rotation of the galactic disk?
A. O-B Associations
D. Globular Clusters
B. H II Regions
E. Giant Molecular Clouds
C. Open Clusters
25. Which of the objects listed below were used to determine the position and speed of our Sun in the Milky Way
galaxy.
A. O-B Associations
D. Globular Clusters
B. H II Regions
E. Giant Molecular Clouds
C. Open Clusters
26. The rotational speed of stars and clouds of gas in the disk of our galaxy can be best characterized by which of
the statements below.
A. The rotation speeds increase with increasing distance from the galactic center.
B. The rotation speeds are fairly flat, neither significantly increasing nor decreasing with distance from the
galactic center.
C. The rotation speeds decrease with increasing distance from the galactic center as gravity weakens.
27. Globular clusters in our galaxy and in other galaxies have been important in the process of measuring galactic
spatial dimensions and distances because they commonly contain which of the objects listed below.
A. H II regions and emission nebula
C. Hot O and B stars
B. Very old population II stars
D. Planetary nebula
E. Cepheid variable stars
28. Which of the objects listed below exhibits a well-defined relationship between their period of oscillation and
their absolute magnitude.
A. Globular clusters
B. H II regions
C. O-B associations
D. Population I stars
E. Cepheid variables
29. Which of the statements listed below best describes the distribution of stars in the disk of spiral galaxies.
A. Stars are nearly uniformly distributed in the disk with only a slight enhancement of O and B stars in the
spiral arms.
B. Stars are concentrated in the spiral arms of the disk with very few stars between the spiral arms.
C. Spiral arms are comprised of G, K, and M type stars, while the region between the arms contains O, B,
and A stars.
D. Spiral arms contain no more stars than the regions between the arms. The spiral arms are more visible
only because of the concentration of H II regions in them.
30. Which of the objects below are found primarily in the galactic halo of the Milky Way.
A. O-B associations
D. Solar-type stars
B. H II regions
E. Globular clusters
C. Layers of galactic gas and dust
31. In the late 19’th century William Herschel unsuccessfully attempted to determine the location of the Sun in the
disk of the Milky Way by using
A. Globular Clusters.
C. Star Counts.
B. Cepheid Variables.
D. RR Lyra stars.
32. The direction to the center of our Milky Way is toward the constellation Sagittarius as determined by
A. the distribution of O and B stars in the disk of our galaxy.
B. the distribution of external galaxies.
C. the direction towards the greatest number of visible stars in the Milky Way.
D. the distribution of Globular Clusters.
33. Within the Milky Way an abundance of gas and dust can be found in
A. the galactic halo, disk, and nucleus
C. the galactic halo only
B. the galactic halo and disk only
D. the galactic disk and nucleus only
34. There are two populations of stars: Population I and Population II. What is the difference between the two
populations?
A. All population II stars have exploded and there are none around today.
B. Population II stars contain only hydrogen and helium while Population I stars contain hydrogen,
helium, and heavier elements.
C. Population II stars are much bigger.
D. Population I stars have a period-luminosity relation, while Population II stars do not.
35. All O,B and A stars are
A. Population I stars.
B. Population II stars.
C. either Population I or II stars.
D. neither Population I or II stars.
36. All K and M stars are
A. Population I stars.
B. Population II stars.
C. either Population I or II stars.
D. neither Population I or II stars.
37. The evidence that there is a large amount of Adark matter” distributed throughout the galactic halo, perhaps 10
times the mass of luminous matter in the galactic disk, comes from which of the observations listed below.
A. The concentration of dust and gas in the galactic mid-plane
B. The flat galactic rotation curve that shows that stars and gas clouds do not decrease in speed with
increasing distance from the galactic center.
C. The residual Doppler shifts of globular clusters.
D. The distribution of O and B stars in spiral arms
E. The high density of stars in the galactic nucleus.
38. Which of the numbers below most closely represents the number of galaxies in the Local Group.
A. 30
C. 3,000
B. 300
D. 30,000
39. Which of the galaxy classes that we have studied is the most common class in The Local Group?
A. Elliptical galaxies
D. Barred spiral galaxies
B. Lenticular galaxies
E. Irregular galaxies.
C. Normal spiral galaxies
40. The Local Group is dominated by the Milky Way and which other galaxy?
A. The Large Magellanic Cloud
C. The Sagittarius dwarf Galaxy
B. The Triangulum Galaxy
D. The Andromeda Galaxy
41. The Cartwheel Galaxy is recognized to be the result of a collision between two galaxies because
A. It has an unusual morphology and shows active star formation.
B. Astronomers have been photographing the collision take place over the past 100 years.
C. Ancient astronomers describe the appearance of the Cartwheel Galaxy in the distance past and modern
astronomers recognize the galaxy has changed.
D. The galaxy can be readily identified as one of the standard Hubble Classification types.
42. The collision between two large spiral galaxies will result in which of the following.
A. A larger Irregular galaxy
C. A larger Elliptical Galaxy
B. A larger Spiral Galaxy
D. A large Globular Cluster
43. A galaxy that contains little or no interstellar gas and dust and no current star formation is most likely which of
the types listed below?
A. Elliptical galaxy
C. Barred spiral galaxy
B. Irregular galaxy
D. Normal Spiral galaxy
44. In approximately 5 billion years our galaxy will be involved in a collision with which of the galaxies listed
below.
A. The Coma Cluster
D. The Andromeda Galaxy, M31
B. The Sombrero Galaxy, M104
E. The Giant Elliptical Galaxy, M87
C. The Small Magellanic Cloud, NGC 292
45. Which of the statements below best describes the Hubble Deep Field?
A. A long exposure photograph towards the center of the Galaxy that shows more stars than previously
photographed.
B. A long exposure infrared image that penetrated deep into the Orion molecular cloud complex revealing
countless young protostars previously unseen.
C. A long multi-wavelength photograph in the visible and infrared of an apparently empty patch of sky
that revealed countless galaxies near the edge of the observable universe.
D. A recent photograph revealing great detail in the field around cluster of galaxies called Stephan’s
Quintet.
46. Which of the statements listed below best explains the large number of elliptical galaxies seen in nearby rich
clusters of galaxies?
A. These clusters have had a great deal of time for their member galaxies to collide and merger.
B. These clusters only appear to be dominated by the giant ellipticals, but there are many more spirals that
cannot be seen because of their very low luminosity.
C. The most common type of galaxy in the universe is the dwarf elliptical, so it follows that we see more
of these galaxies in clusters.
D. The light from nearby clusters of galaxies has taken millions of years to reach us, so we see them as
they looked in the distant past. In the distant past of the universe giant elliptical galaxies were more
common.
47. Which of the types of galaxies listed below is believed to be the most numerous in the Universe?
A. Normal Spirals
D. Dwarf Ellipticals
B. Barred Spirals
E. Irregulars
C. Giant Ellipticals
48. Which of the galaxies types listed below is considered to contain the most massive galaxies?
A. Normal Spirals
D. Irregulars
B. Barred Spirals
E. Peculiars
C. Ellipticals
49.
50.
The spin flip of an electron around a neutral hydrogen atom releases or absorbs which of the following?
A. A red photon characteristic in HII regions.
B. A UV photon that ionizes the gas around it.
C. A radio photon of 21-cm wavelength that travels unimpeded through the galactic disk.
D. A neutrino that passes through ordinary matter without effect.
Which of the statements below best describes the spiral arms seen in some galaxies?
A. Spiral arms are a long-lived pattern of mostly Population I stars that eventually wind-up into a tighter
pattern due to the speeds of stars at different distances from the center. Thus a galaxy’s classification
will change as its arms become more tightly wrapped.
B. Spiral arms are nearly completely comprised of young luminous stars that have exceedingly short
lifetimes (on astronomical timescales). Thus the lifetimes of spiral arms are short and are transient
features in a galaxy. In a few 10’s of million years spiral arms will fade in galaxies as the short-lived
stars supernova.
C. Spiral arms represent permanent features in spiral galaxies because they are the result of a permanent
highly concentrated group of stars that is fixed in the galaxy. The very high density of stars in the
spiral arms gives them their exceptional luminosity.
D. Spiral arms are a manifestation of a spiral density wave that is slowly circulating around the disk of the
galaxy. The persistence of the spiral pattern requires the continual excitation of this wave by some
external or internal mechanism.