Term
| In the H-R diagram, what are the two most important types of data plotted? |
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Definition
| spectral classes and absolute magnitudes (Correct) |
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Term
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Definition
| temperature versus luminosity. (Correct) |
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Term
| Rigel has an apparent magnitude of + 0.18 and Betelgeuse an apparent magnitude of +0.45. What can you conclude from this? |
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Definition
| Rigel is brighter than Betelgeuse. (Correct) |
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Term
| On the H-R diagram, the bright blue stars that dominate the naked-eye sky lie |
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Definition
| at the top left (Correct) |
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Term
| Compared to the size of the Sun, stars of all types range from |
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Definition
| 0.01 to over 1,000 solar radii (Correct) |
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Term
Which of these binaries would appear most similar in color telescopically?
O2V and M4Ia
F0V and G9III
A2Ia and F7Ia
M1V and K9V
F3IV and G8III |
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Definition
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Term
A star is 10 parsecs from Earth. Which statement is true?
The star's apparent magnitude is smaller than its absolute magnitude.
The star is about 33 light years away.
The star is in a different galaxy.
The star's parallax is 1.0 arc seconds.
The star's apparent magnitude is larger than its absolute magnitude. |
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Definition
| The star is about 33 light years away. (Correct) |
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Term
Which statement about stellar motion is incorrect?
Radial velocity is measured by the Doppler shifts of the spectral lines.
The space velocity can be found from the radial and transverse velocities.
The closer stars usually show larger proper motions.
Proper motion is measured in intervals of six months.
All of these are correct. |
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Definition
| Proper motion is measured in intervals of six months. (Correct) |
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Term
| The Doppler shift is used to find |
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Definition
| spectroscopic binaries (Correct) |
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Term
| A star has a parallax of .05." Its distance is |
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Definition
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Term
| On the H-R diagram, red supergiants like Betelgeuse lie |
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Definition
| at the top right. (Correct) |
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Term
| The star's color index is a quick way of determining its |
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Definition
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Term
| 3. On the H-R diagram, white dwarfs Sirius B and Procyon B lie |
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Definition
| at the lower left. (Correct) |
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Term
| 14. How much brighter will a 4th magnitude star appear than a 6th magnitude star? |
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Definition
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Term
| 15. Binary stars separated enough to be resolved in a telescope are called |
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Definition
| visual binaries. (Correct) |
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Term
| 16. Stellar masses are measured directly by observations of the motions of |
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Definition
eclipsing binary systems.
spectroscopic binary systems.
visual binary systems. (Correct) |
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Term
| 17. A star's absolute magnitude is its apparent brightness as seen from |
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Definition
| 10 parsecs distance. (Correct) |
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Term
| 18. Which of these stars would be the hottest? |
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Definition
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Term
| 19. Two stars both have parallaxes of 0.023", but star A has apparent magnitude +2.3, while star B is magnitude +7.3. Which statement is true? |
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Definition
| Star A is both 100× brighter and more luminous than star B. (Correct) |
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Term
| 20. If Vega is apparent magnitude zero, and Deneb first magnitude, then |
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Definition
| Vega is 2.5× brighter than Deneb. (Correct) |
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Term
| 21. Compared to a type A0 star, a type A9 star is |
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Definition
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Term
| 22. On the H-R diagram, the Sun lies |
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Definition
| about the middle of the main sequence. (Correct) |
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Term
| 23. A star near the lower right of the H-R diagram is likely to be |
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Definition
| red, with low luminosity. (Correct) |
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Term
| 24. What can be said with certainty about a red star and a blue star? |
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Definition
| The blue star is hotter than the red star. (Correct) |
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Term
| 25. What physical property of a star does the spectral type measure? |
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Definition
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Term
| 26. On a night when a human eye can see a fourth magnitude star, a 60mm telescope, which can see something 100 times fainter than the human eye, would be able to just barely detect |
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Definition
| ninth magnitude Barnard's Star. (Correct) |
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Term
1. It is important to study interstellar dust because
this is where stars are formed.
there is almost as much mass between the stars as therre is in them.
old stars expel their matter here when they die.
all of the above. |
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Definition
| all of the above. (Correct) |
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Term
| 2. A large gas cloud in the interstellar medium that contains several type O and B stars would appear to us as |
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Definition
| an emission nebula. (Correct) |
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Term
| 3. The spectra of interstellar gas clouds show that they have the same basic composition as |
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Definition
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Term
| 4. Reflection nebula have their blue colour because |
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Definition
| the interstellar dust deflects the blue light. (Correct) |
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Term
| 5. Interstellar matter is distributed very evenly throughout the galaxy. |
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Definition
|
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Term
| 6. What happens to light passing through even thin clouds of dust? |
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Definition
| It dims and reddens the light of all more distant stars. (Correct) |
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Term
| 7. What is true of emission nebula? |
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Definition
they produce an emission spectrum.
their temperature can exceed that of our sun.
they are often part of much larger interstellar clouds.
they are bigger than earth. |
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Term
| 8. Due to absorption of shorter wavelengths by interstellar dust clouds, distant stars appear |
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Definition
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Term
| 9. There is as much mass in the voids between the stars as in the stars themselves. |
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Definition
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Term
| 10. Which statement is true about the interstellar medium? |
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Definition
| We know more about the gas than the dust. (Correct) |
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Term
| 11. Which statement about dark dust clouds is true? |
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Definition
| They can be penetrated only with longer wavelengths such as radio and infrared. (Correct) |
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Term
| 12. The average temperature of the typical dark dust cloud is about |
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Definition
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Term
| 13. The density of interstellar dust is very low, yet it still blocks starlight because |
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Definition
| the dust particles are about the same size as the light waves they absorb. (Correct) |
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Term
| 14. Which of these is not a consequence of dust in the interstellar medium? |
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Definition
| red light from the emission nebulae (Correct) |
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Term
| 15. Why are dark dust clouds largely misnamed? |
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Definition
| They contain much more gas than dust. (Correct) |
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Term
| 17. Neutral hydrogen atoms are best studied from their energy given off as |
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Definition
| 21-cm waves in the radio region. (Correct) |
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Term
| 18. When an electron in a hydrogen atom changes its spin from the same to the opposite direction as the proton, it |
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Definition
| emits a radio wave photon. (Correct) |
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Term
| 19. What two things are needed to create an emission nebula? |
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Definition
| hot stars and interstellar gas, particularly hydrogen (Correct) |
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Term
| 20. What is the primary visible color of an emission nebula? |
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Definition
| red due to the Hα line of hydrogen (Correct) |
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Term
| 21. The 21-cm line of hydrogen is strongly absorbed by interstellar dust. |
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Definition
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Term
| 22. Some regions along the plane of the Milky Way appear dark because |
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Definition
| stars in that region are hidden by dark dust particles. (Correct) |
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Term
| 1. A cloud fragment too small to collapse into a main sequence star becomes a |
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Definition
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Term
| 2. Which of these would typically be the brightest star in a young open cluster? |
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Definition
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Term
| 3. Paradoxically, while the core of the red giant is contracting and heating up, its radiation pressure causes its photosphere to swell up and cool off. |
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Definition
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Term
| 4. All globular clusters in our Milky Way are about how old? |
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Definition
| around ten billion years old (Correct) |
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Term
| 5. Which is characteristic of globular star clusters? |
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Definition
| old age and hundreds of thousands of stars, only about 30 ly wide (Correct) |
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Term
| 6. A star (no matter what its mass) spends most of its life |
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Definition
| as a main-sequence star. (Correct) |
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Term
| 7. Why are star clusters ideal "laboratories" for stellar evolution? |
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Definition
| Their stars are all about the same age, composition, and distance from us. (Correct) |
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Term
| 8. How long does it take an M-type star to reach the main sequence, compared to a star like our sun? |
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Definition
| about twenty times longer |
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Term
| 9. Which of these is true of planetary nebulae? |
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Definition
| They are ejected envelopes surrounding a highly evolved low-mass star. (Correct) |
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Term
| 10. When a low mass star first runs short of hydrogen in its core, it becomes brighter because |
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Definition
| the core contracts, raising the temperature and extending the hydrogen burning shell outward. (Correct) |
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Term
| 11. When the outer envelope of a red giant escapes, the remaining carbon core is called a |
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Definition
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Term
| 12. The single most important determinant of the temperature, density, radius, luminosity, and pace of evolution of a protostar is its |
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Definition
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Term
| 13. Which statement about the stages of starbirth is false? |
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Definition
| nuclear reactions begin in the core by stage 4. (Correct) |
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Term
| 14. A(n) ________ represents a relatively peaceful mass loss as a red giant becomes a white dwarf. |
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Definition
| planetary nebula (Correct) |
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Term
| 15. Stars evolve along the main sequence. |
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Definition
|
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Term
| 16. Can a star become a red giant more than once? |
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Definition
| yes, before and after the helium flash (Correct) |
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Term
| 17. What are the characteristics of an open cluster of stars? |
|
Definition
| a few hundred, mostly main-sequence stars (Correct) |
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Term
| 18. On an H-R diagram, a protostar would be |
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Definition
| above and to the right of the main sequence. (Correct) |
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Term
| 19. Which of these would typically be among the brightest stars in an ancient globular cluster? |
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Definition
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Term
| 20. Which of these evolutionary paths is the fate of our Sun? |
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Definition
| planetary nebula (Correct) |
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Term
| 21. A surface explosion on a white dwarf, caused by falling matter from the atmosphere of its binary companion, creates what kind of object? |
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Definition
|
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Term
| 22. During the T-Tauri phase of a protostar, it |
|
Definition
| may develop very strong winds. (Correct) |
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Term
| 23. What temperature is needed to fuse helium into carbon? |
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Definition
|
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Term
| 24. Approximately how many brown dwarfs are believed to exist in the Milky Way galaxy? |
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Definition
| one hundred billion (Correct) |
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Term
| 25. At what core temperature does hydrogen begin to fuse to helium? |
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Definition
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Term
| 26. A fragment of a collapsing gas cloud that comes to equilibrium with a central temperature of 4 million K will become a |
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Definition
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Term
| 27. The helium flash converts helium nuclei into |
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Definition
|
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Term
| 28. When a star's inward gravity and outward pressure are balanced, the star is said to be |
|
Definition
| in hydrostatic equilibrium. (Correct) |
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Term
| 1. As a 6 solar-mass star leaves the main sequence on its way to becoming a red supergiant, its luminosity |
|
Definition
| remains roughly constant. (Correct) |
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Term
| 2. An object more massive than the Sun, but roughly the size of a city, is a |
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Definition
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Term
| 3. The brightest stars in a young open cluster will be |
|
Definition
| massive blue main-sequence stars. (Correct) |
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Term
| 4. You would expect millisecond pulsars to be |
|
Definition
| part of a binary system. (Correct) |
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Term
| 5. A recurrent nova could eventually build up to a |
|
Definition
| Type I supernova. (Correct) |
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Term
| 6. Which of these events is not possible? |
|
Definition
| white dwarfs and companion stars producing recurrent Type I supernova events (Correct) |
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Term
| 7. Neutron stars do not have |
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Definition
| rotation periods comparable to the Sun's. (Correct) |
|
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Term
|
Definition
| spin very rapidly when they're young. (Correct) |
|
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Term
| 9. As a star's evolution approaches the Type II supernova, we find |
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Definition
the heavier the element, the less time it will burn for.
the heavier the element, the higher the temperature to fuse it.
photo disintegration of iron nuclei begins at 10 billion K to ignite the supernova.
helium to carbon fusion takes at least 100 million K to start.
All of the above are correct. (Correct) |
|
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Term
| 10. In the Lighthouse Model, |
|
Definition
| if the beam sweeps across us, we will detect a pulse of radiation. (Correct) |
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Term
| 11. What is the typical age for a globular cluster associated with our Milky Way? |
|
Definition
| 10-12 billion years (Correct) |
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Term
| 12. What can you conclude about a Type I supernova? |
|
Definition
| It was originally a low-mass star. (Correct) |
|
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Term
| 13. X-ray bursters occur in binary star systems. The two types of stars that must be present to make up such an object are |
|
Definition
a main-sequence or giant star and a neutron star in a mass transfer binary.
(Correct) |
|
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Term
|
Definition
| not found yet; the oldest, coldest white dwarf in the Galaxy has not cooled enough yet. (Correct) |
|
|
Term
| 15. The brightest stars in aging globular clusters will be |
|
Definition
| red supergiants like Betelgeuse and Antares.(Correct) |
|
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Term
| 16. Most pulsars are observed as ________ sources. |
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Definition
|
|
Term
| 17. For a white dwarf to explode entirely as a Type I supernova, its mass must be |
|
Definition
| 1.4 solar masses, the Chandrasekhar limit. (Correct) |
|
|
Term
| 18. Two important properties of young neutron stars are |
|
Definition
| extremely rapid rotation and a strong magnetic field. (Correct) |
|
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Term
| 19. Of the elements in your body, the only one not formed in stars is |
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Definition
|
|
Term
| 20. Which of these does not depend on a close binary system to occur? |
|
Definition
| a Type II supernova (Correct) |
|
|
Term
| 21. Type II supernovae occur when their cores start making |
|
Definition
|
|
Term
| 22. The mass range for neutron stars is |
|
Definition
| 1 to 3 solar masses. (Correct) |
|
|
Term
| 23. An iron core cannot support a star because |
|
Definition
| iron cannot fuse with other nuclei to produce energy. (Correct) |
|
|
Term
| 24. Compared to a cluster containing type O and B stars, a cluster with only type F and cooler stars will be |
|
Definition
|
|
Term
| 25. In a neutron star, the core is |
|
Definition
| made of compressed neutrons in contact with each other. (Correct) |
|
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Term
| 26. Which is used observationally to determine the age of a star cluster? |
|
Definition
| the luminosity of the main-sequence turn-off point (Correct) |
|
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Term
| 27. Which of the following best describes the evolutionary track of the most massive stars? |
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Definition
| horizontal right (Correct) |
|
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Term
| 16. Complex molecules in the interstellar medium are found |
|
Definition
| primarily in the dense dust clouds. (Correct) |
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|
