Question 1

Absorption lines due to interstellar gas

Accepted Answer

A)  are wider than the lines from stars because the gas is hotter than most stars.
B)  are narrower than the lines from stars because the gas has a lower pressure than stars.
C)  indicate that the interstellar medium contains dust.
D)  indicate that the interstellar medium is expanding away from the Sun.
E)  None of the other choices are correct.F) B) and C)
G) All of the above

Question 2

-The above image is a/an _________ wavelength image of a reflection nebula.

Accepted Answer

A)  infrared
B)  visual
C)  radio
D)  X-rayE) B) and C)
F) A) and C)

Question 3

The creation of ________ require(s)  that a young hot star (T ≈ 25,000 K)  be relatively nearby.

Accepted Answer

A)  emission nebulae
B)  HI regions
C)  molecular clouds
D)  the cool gas of the interstellar medium
E)  21-cm radiationF) A) and B)
G) None of the above

Question 4

A ZAMS star evolves __________ and to the __________ on the H-R diagram because ________________.

Accepted Answer

A)  downward, left, the core expands which causes the outer layers to expand
B)  upward, right, the core contracts which causes the outer layers to expand
C)  upward, left, the core expands which causes the outer layers to contract
D)  downward, right, the core contracts which causes the outer layers to contractE) A) and B)
F) All of the above

Question 5

_________ are small luminous nebulae excited by nearby young stars.

Accepted Answer

A)  T Tauri stars
B)  Herbig-Haro objects
C)  O associations
D)  Bok Globule
E)  Giant molecular cloudsF) D) and E)
G) A) and E)

Question 6

in the following cartoon image of Orion, where would you find the Orion nebula

Accepted Answer

A)  below the belt (i.e., three white stars)  but above the lower right blue and lower left white stars
B)  above the belt (i.e., three white stars)  but below the upper red and the upper white stars
C)  in the belt, that is, among the three white stars
D)  outside the white linesE) B) and D)
F) B) and C)

Question 7

What evidence indicates protostars have formed

Accepted Answer

A)  jets
B)  bipolar outflows
C)  protostellar disks
D)  All of the other choices are correct.E) C) and D)
F) B) and C)

Question 8

Why are massive stars more luminous than low mass stars That is, why is there a mass-luminosity relation

Accepted Answer

To understand the mass-luminosity relati...

Question 9

Explain what keeps the nuclear reactions in a star under control; i.e., what would happen if too large an amount of energy is released in the center

Accepted Answer

If the star makes slightly too much ener...

Question 10

In the collapse of a protostar ____________________ energy is converted to ____________________ energy.

Accepted Answer

The answer of In the collapse of a protostar ____________________...

Question 11

What causes the outward gas pressure that balances the inward pull of gravity in a main-sequence star

Accepted Answer

A)  the rapid outward flow of gas
B)  the rapid inward flow of the gas
C)  the high temperature of the gas
D)  the high density of the gas
E)  the high temperature and the high density of the gasF) D) and E)
G) B) and D)

Question 12

Some young star clusters contain large numbers of protostars.

Accepted Answer

A) True 
 B)False

Question 13

Energy transport by ____________________ is important when photons cannot readily travel through a gas.

Accepted Answer

The answer of Energy transport by ____________________ is important when...

Question 14

The lower edge of the main-sequence band is known as ________ and represents the location in the H-R diagram at which stars begin their lives as main-sequence stars.

Accepted Answer

A)  the Coulomb barrier
B)  hydrostatic equilibrium
C)  the birth line
D)  the zero-age main sequence
E)  the evolutionary trackF) B) and C)
G) A) and E)

Question 15

Due to the dust in the interstellar medium, a distant star will appear to an observer on Earth to be

Accepted Answer

A)  brighter and cooler than it really is.
B)  brighter and hotter than it really is.
C)  fainter and cooler than it really is.
D)  fainter and hotter than it really is.
E)  unchanged in brightness or apparent color.F) A) and B)
G) None of the above

Question 16

A(n) ____________________ is a cool, dense cloud of dust and gas that is undergoing gravitational contraction.

Accepted Answer

The answer of A(n) ____________________ is a cool, dense cloud...

Question 17

The lowest-mass object that can initiate thermonuclear fusion of hydrogen has a mass of about

Accepted Answer

A)  1 solar masses.
B)  80 solar masses.
C)  8 solar masses.
D)  0.08 solar masses.
E)  0.001 solar masses.F) A) and B)
G) A) and E)

Question 18

-The above image is an example of a/an ____________.

Accepted Answer

A)  cluster of stars producing reflection nebula
B)  T association
C)  OB association
D)  Trapezium clusterE) B) and C)
F) A) and D)

Question 19

How long can a 1-solar-mass star live

Accepted Answer

A)  0.5 solar lifetimes
B)  1 solar lifetime
C)  2 solar lifetimes
D)  10 solar lifetimesE) A) and B)
F) None of the above

Question 20

What observations demonstrate the existence of an interstellar medium

Accepted Answer

One way to investigate properties of the...

Exam 9: The Formation and Structure of Stars

Explain what keeps the nuclear reactions in a star under control; i.e., what would happen if too large an amount of energy is released in the center

Correct AnswerverifiedIf the star makes slightly too much ener...View AnswerShow Answer

-The above image is an example of a/an ____________.

Correct AnswerverifiedShow Answer

What observations demonstrate the existence of an interstellar medium

Correct AnswerverifiedOne way to investigate properties of the...View AnswerShow Answer

_________ are small luminous nebulae excited by nearby young stars.

Correct AnswerverifiedShow Answer

What causes the outward gas pressure that balances the inward pull of gravity in a main-sequence star

Correct AnswerverifiedShow Answer

Some young star clusters contain large numbers of protostars.

Correct AnswerverifiedShow Answer

In the collapse of a protostar ____________________ energy is converted to ____________________ energy.

Correct AnswerverifiedShow Answer

Why are massive stars more luminous than low mass stars That is, why is there a mass-luminosity relation

Correct AnswerverifiedTo understand the mass-luminosity relati...View AnswerShow Answer

How long can a 1-solar-mass star live

Correct AnswerverifiedShow Answer

A(n) ____________________ is a cool, dense cloud of dust and gas that is undergoing gravitational contraction.

Correct AnswerverifiedShow Answer

The lowest-mass object that can initiate thermonuclear fusion of hydrogen has a mass of about

Correct AnswerverifiedShow Answer

The creation of ________ require(s) that a young hot star (T ≈ 25,000 K) be relatively nearby.

Correct AnswerverifiedShow Answer

Absorption lines due to interstellar gas

Correct AnswerverifiedShow Answer

in the following cartoon image of Orion, where would you find the Orion nebula

Correct AnswerverifiedShow Answer

The lower edge of the main-sequence band is known as ________ and represents the location in the H-R diagram at which stars begin their lives as main-sequence stars.

Correct AnswerverifiedShow Answer

What evidence indicates protostars have formed

Correct AnswerverifiedShow Answer

Due to the dust in the interstellar medium, a distant star will appear to an observer on Earth to be

Correct AnswerverifiedShow Answer

Energy transport by ____________________ is important when photons cannot readily travel through a gas.

Correct AnswerverifiedShow Answer

A ZAMS star evolves __________ and to the __________ on the H-R diagram because ________________.

Correct AnswerverifiedShow Answer

-The above image is a/an _________ wavelength image of a reflection nebula.

Correct AnswerverifiedShow Answer

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If the star makes slightly too much ener...
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One way to investigate properties of the...
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In the collapse of a protostar energy is converted to energy.

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To understand the mass-luminosity relati...
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A ZAMS star evolves and to the on the H-R diagram because ________.

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