Question 1

Which of the following is most strongly affected by interstellar dust?

Accepted Answer

A)   infrared light
B)   visible light
C)   microwaves
D)   radio wavesE) A) and B)
F) A) and C)

Question 2

How might an astronomer measure the initial mass function?

Accepted Answer

A)   catalog the masses of all the stars in the Milky Way
B)   catalog the masses of all nearby galaxies
C)   catalog the masses of all the molecular clouds in the Milky Way
D)   catalog the masses of all the stars in a young open clusterE) C) and D)
F) None of the above

Question 3

What is the typical size of an interstellar dust grain?

Accepted Answer

A)   50 microns
B)   5 microns
C)   5 nm
D)   500 nmE) B) and C)
F) A) and D)

Question 4

Which of the following is an important effect of interstellar dust?

Accepted Answer

A)   a platform for the formation of molecules
B)   pressure equilibrium in the interstellar medium
C)   a source of diagnostic emission lines
D)   heating of the interstellar mediumE) None of the above
F) C) and D)

Question 5

What does it mean for a giant molecular cloud to have a hierarchy of structures?

Accepted Answer

The cloud has smalle...

Question 6

A brown dwarf is a:

Accepted Answer

A)   low-mass star.
B)   failed star.
C)   stellar remnant supported by electron degeneracy pressure.
D)   stellar remnant supported by neutron degeneracy pressure.E) A) and C)
F) A) and B)

Question 7

In what wavelength range do protostars emit most of their energy?

Accepted Answer

A)   optical
B)   radio
C)   infrared
D)   ultravioletE) A) and B)
F) All of the above

Question 8

Which of the following provides the best example of turbulence?

Accepted Answer

A)   a molecular cloud with large whorls containing many smaller whorls
B)   a jet launched at near the speed of light by a supermassive black hole
C)   a large network of convection cells inside a star
D)   an accretion disk rotating around a black holeE) B) and C)
F) C) and D)

Question 9

A protostar becomes a star when:

Accepted Answer

A)   its luminosity reaches a maximum.
B)   its surface temperature reaches 5,000 K.
C)   it loses all its gravitational energy.
D)   nuclear fusion begins.E) A) and B)
F) All of the above

Question 10

What is the wavelength of radiation produced by the system in the figure below?

Accepted Answer

A)   91 nm
B)   121 nm
C)   656 nm
D)   21 cmE) A) and B)
F) A) and C)

Question 11

Suppose a star forms with 10 times the mass of the Sun and without any elements heavier than helium.How will the central temperature of this star compare to a star with the same mass but the same composition as the Sun?

Accepted Answer

The metal-free star will be ho...

Question 12

An interstellar gas cloud with a density of 100 particles per cubic centimeter and with a temperature of 100 K is in equilibrium with a medium with a density of 0.1 particles per cubic centimeter and 10⁶ K.What is the most likely explanation?

Accepted Answer

A)   supernova blast waves
B)   photoionization
C)   turbulence
D)   the ideal gas lawE) A) and B)
F) A) and C)

Question 13

Why does the initial mass function of stars differ from the actual distribution of stars in the Milky Way at the present day?

Accepted Answer

The initial mass function describes the ...

Question 14

Which of the following nuclei can a compact astronomical object with a mass of 0.05 MSun create through fusion?

Accepted Answer

A)   none
B)   deuterium
C)   helium
D)   carbonE) None of the above
F) All of the above

Question 15

List the five phases of the interstellar medium in order from coolest to hottest.

Accepted Answer

Molecular clouds,H I...

Question 16

Why do massive stars use the CNO cycle to generate energy,rather than the proton-proton chain?

Accepted Answer

A)   It is more temperature sensitive.
B)   Massive stars have more carbon.
C)   It produces more energy per helium nucleus.
D)   It uses up the carbon too quickly in low-mass stars.E) None of the above
F) B) and C)

Question 17

What would happen to the Milky Way's interstellar medium if more supernovae occurred than usual?

Accepted Answer

It would b...

Question 18

Massive stars on the main sequence generate energy through the:

Accepted Answer

A)   proton-proton chain.
B)   CNO cycle.
C)   triple alpha reaction.
D)   onion model.E) C) and D)
F) A) and C)

Question 19

What are two reasons that molecules are so abundant within giant molecular clouds?

Accepted Answer

The high densities enable them...

Question 20

A Herbig-Haro object is moving at 100 km/s and lies 10 parsecs from a protostar.What is a lower limit for the lifetime of the protostar? Express your answer in years.

Accepted Answer

The answer of A Herbig-Haro object is moving at 100...

Exam 12: Nursery of the Stars: the Interstellar Medium and Star Formation

In what wavelength range do protostars emit most of their energy?

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Massive stars on the main sequence generate energy through the:

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A brown dwarf is a:

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Which of the following nuclei can a compact astronomical object with a mass of 0.05 MSun create through fusion?

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A protostar becomes a star when:

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What would happen to the Milky Way's interstellar medium if more supernovae occurred than usual?

Correct AnswerverifiedIt would b...View AnswerShow Answer

Which of the following is an important effect of interstellar dust?

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Why does the initial mass function of stars differ from the actual distribution of stars in the Milky Way at the present day?

Correct AnswerverifiedThe initial mass function describes the ...View AnswerShow Answer

Which of the following provides the best example of turbulence?

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Which of the following is most strongly affected by interstellar dust?

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What is the wavelength of radiation produced by the system in the figure below?

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List the five phases of the interstellar medium in order from coolest to hottest.

Correct AnswerverifiedMolecular clouds,H I...View AnswerShow Answer

What does it mean for a giant molecular cloud to have a hierarchy of structures?

Correct AnswerverifiedThe cloud has smalle...View AnswerShow Answer

An interstellar gas cloud with a density of 100 particles per cubic centimeter and with a temperature of 100 K is in equilibrium with a medium with a density of 0.1 particles per cubic centimeter and 10⁶ K.What is the most likely explanation?

Correct AnswerverifiedShow Answer

Suppose a star forms with 10 times the mass of the Sun and without any elements heavier than helium.How will the central temperature of this star compare to a star with the same mass but the same composition as the Sun?

Correct AnswerverifiedThe metal-free star will be ho...View AnswerShow Answer

A Herbig-Haro object is moving at 100 km/s and lies 10 parsecs from a protostar.What is a lower limit for the lifetime of the protostar? Express your answer in years.

Correct AnswerverifiedShow Answer

How might an astronomer measure the initial mass function?

Correct AnswerverifiedShow Answer

What is the typical size of an interstellar dust grain?

Correct AnswerverifiedShow Answer

What are two reasons that molecules are so abundant within giant molecular clouds?

Correct AnswerverifiedThe high densities enable them...View AnswerShow Answer

Why do massive stars use the CNO cycle to generate energy,rather than the proton-proton chain?

Correct AnswerverifiedShow Answer

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Which of the following nuclei can a compact astronomical object with a mass of 0.05 M_Sun create through fusion?

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It would b...
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Correct Answer
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The initial mass function describes the ...
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Molecular clouds,H I...
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The cloud has smalle...
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The metal-free star will be ho...
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The high densities enable them...
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