Question 1

Interstellar gas clouds may collapse to form stars if they

Accepted Answer

A)  have very high temperatures. 
B)  encounter a shock wave. 
C)  rotate rapidly. 
D)  are located near main sequence spectral type K and M stars. 
E)  all of the above. 
A)  have very high temperatures. 
B)  encounter a shock wave. 
C)  rotate rapidly. 
D)  are located near main sequence spectral type K and M stars. 
E)  all of the above.

Question 2

What characteristic of a star primarily determines its location on the main sequence?

Accepted Answer

A)  age 
B)  distance from the galactic center 
C)  mass 
D)  space motion 
E)  radius 
A)  age 
B)  distance from the galactic center 
C)  mass 
D)  space motion 
E)  radius

Question 3

The pressure of an interstellar gas cloud depends on the cloud's ____________________ and ____________________.

Accepted Answer

temperatur

Question 4

What is the difference between the proton-proton chain and the CNO cycle?

Accepted Answer

The answer of What is the difference between the proton-proton...

Question 5

The free-fall contraction of a molecular cloud

Accepted Answer

A)  can be initiated by shock waves from supernovae. 
B)  can be initiated by nearby spectral type G stars. 
C)  can be initiated by the rotation of the cloud. 
D)  causes the cloud to become transparent to ultraviolet radiation. 
E)  causes the particles in the cloud to decrease the speed with which they move. 
A)  can be initiated by shock waves from supernovae. 
B)  can be initiated by nearby spectral type G stars. 
C)  can be initiated by the rotation of the cloud. 
D)  causes the cloud to become transparent to ultraviolet radiation. 
E)  causes the particles in the cloud to decrease the speed with which they move.

Question 6

The youngest stars in the Orion Nebula and other star-forming regions also show

Accepted Answer

A)  circumstellar disks. 
B)  jets. 
C)  both A and B 
A)  circumstellar disks. 
B)  jets. 
C)  both A and B

Question 7

What is the lifetime on the main sequence of a 2-solar-mass star compared to the approximately 10-billion-year life of our sun? Pick the best answer.

Accepted Answer

A)  1.8*1011 years 
B)  1.8*1010 years 
C)  1.8*109 years 
D)  1.8*106 years 
E)  1.8*103 years 
A)  1.8*1011 years 
B)  1.8*1010 years 
C)  1.8*109 years 
D)  1.8*106 years 
E)  1.8*103 years

Question 8

Why are interstellar absorption lines so narrow compared to the width of lines which originate in the photospheres of stars?

Accepted Answer

The answer of Why are interstellar absorption lines so narrow...

Question 9

While on the main sequence a star's primary energy source comes from

Accepted Answer

A)  nuclear fusion. 
B)  nuclear fission. 
C)  gravitational potential energy. 
D)  magnetic fields. 
A)  nuclear fusion. 
B)  nuclear fission. 
C)  gravitational potential energy. 
D)  magnetic fields.

Question 10

Why do nuclear reactions in a star occur only near its center?

Accepted Answer

The answer of Why do nuclear reactions in a star...

Question 11

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 12

The thermal motions of the atoms in a gas cloud can make it collapse to form a protostar.

Accepted Answer

A) True 
 B)False

Question 13

The H-R diagram of a young star cluster shows

Accepted Answer

A)  that high-mass stars have not yet reached the main sequence yet. 
B)  that low-mass stars have not yet reached the main sequence yet. 
C)  mainly giant stars. 
D)  no stars since none have reached the main sequence yet. 
A)  that high-mass stars have not yet reached the main sequence yet. 
B)  that low-mass stars have not yet reached the main sequence yet. 
C)  mainly giant stars. 
D)  no stars since none have reached the main sequence yet.

Question 14

What observations demonstrate the existence of an interstellar medium?

Accepted Answer

The answer of What observations demonstrate the existence of an...

Question 15

Star clusters are important to the study the stellar evolution because stars in a given cluster have the same

Accepted Answer

A)  temperature. 
B)  mass. 
C)  age. 
D)  luminosity. 
A)  temperature. 
B)  mass. 
C)  age. 
D)  luminosity.

Question 16

Ionization from the ____________________ star in the Orion nebula makes it ____________________ brightly.

Accepted Answer

The answer of Ionization from the ____________________ star in the...

Question 17

____ is the thermonuclear fusion of hydrogen to form helium operating in the cores of massive stars on the main sequence.

Accepted Answer

A)  The CNO cycle 
B)  The proton-proton chain 
C)  Hydrostatic equilibrium 
D)  The neutrino process 
E)  None of the above 
A)  The CNO cycle 
B)  The proton-proton chain 
C)  Hydrostatic equilibrium 
D)  The neutrino process 
E)  None of the above

Question 18

The diagram below is an H-R diagram. The line indicates the location of the main sequence. Which of the five labeled locations on the H-R diagram indicates a luminosity and temperature similar to that of a T Tauri star?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 19

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

Question 20

The creation of ____ require(s) that a young hot star (T $\approx$ 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 radiation 
A)  emission nebulae 
B)  HI regions 
C)  molecular clouds 
D)  the cool gas of the interstellar medium 
E)  21-cm radiation

Interstellar gas clouds may collapse to form stars if they

What characteristic of a star primarily determines its location on the main sequence?

The pressure of an interstellar gas cloud depends on the cloud's and .

What is the difference between the proton-proton chain and the CNO cycle?

The free-fall contraction of a molecular cloud

The youngest stars in the Orion Nebula and other star-forming regions also show

What is the lifetime on the main sequence of a 2-solar-mass star compared to the approximately 10-billion-year life of our sun? Pick the best answer.

Why are interstellar absorption lines so narrow compared to the width of lines which originate in the photospheres of stars?

While on the main sequence a star's primary energy source comes from

Why do nuclear reactions in a star occur only near its center?

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

The thermal motions of the atoms in a gas cloud can make it collapse to form a protostar.

The H-R diagram of a young star cluster shows

What observations demonstrate the existence of an interstellar medium?

Star clusters are important to the study the stellar evolution because stars in a given cluster have the same

Ionization from the star in the Orion nebula makes it brightly.

____ is the thermonuclear fusion of hydrogen to form helium operating in the cores of massive stars on the main sequence.

The diagram below is an H-R diagram. The line indicates the location of the main sequence. Which of the five labeled locations on the H-R diagram indicates a luminosity and temperature similar to that of a T Tauri star?

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.

The creation of ____ require(s) that a young hot star (T $\approx$ 25,000 K) be relatively nearby.

Here and Now

A Users Guide to the Sky

Cycles of the Sun and Moon

The Origin of Modern Astronomy

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Deaths of Stars

Neutron Stars and Black Holes

The Milky Way Galaxy

Galaxies: Normal and Active

Modern Cosmology

The Origin of the Solar System

Earth and Moon: Bases for Comparative Planetology

Mercury, Venus and Mars

The Outer Solar System

Meteorites, Asteroids, and Comets

Astrobiology: Life on Other Worlds

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Exam 9: The Formation and Structure of Stars

Interstellar gas clouds may collapse to form stars if they

What characteristic of a star primarily determines its location on the main sequence?

The pressure of an interstellar gas cloud depends on the cloud's ____________________ and ____________________.

What is the difference between the proton-proton chain and the CNO cycle?

The free-fall contraction of a molecular cloud

The youngest stars in the Orion Nebula and other star-forming regions also show

What is the lifetime on the main sequence of a 2-solar-mass star compared to the approximately 10-billion-year life of our sun? Pick the best answer.

Why are interstellar absorption lines so narrow compared to the width of lines which originate in the photospheres of stars?

While on the main sequence a star's primary energy source comes from

Why do nuclear reactions in a star occur only near its center?

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

The thermal motions of the atoms in a gas cloud can make it collapse to form a protostar.

The H-R diagram of a young star cluster shows

What observations demonstrate the existence of an interstellar medium?

Star clusters are important to the study the stellar evolution because stars in a given cluster have the same

Ionization from the ____________________ star in the Orion nebula makes it ____________________ brightly.

____ is the thermonuclear fusion of hydrogen to form helium operating in the cores of massive stars on the main sequence.

The diagram below is an H-R diagram. The line indicates the location of the main sequence. Which of the five labeled locations on the H-R diagram indicates a luminosity and temperature similar to that of a T Tauri star?

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.

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

Here and Now

A Users Guide to the Sky

Cycles of the Sun and Moon

The Origin of Modern Astronomy

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Deaths of Stars

Neutron Stars and Black Holes

The Milky Way Galaxy

Galaxies: Normal and Active

Modern Cosmology

The Origin of the Solar System

Earth and Moon: Bases for Comparative Planetology

Mercury, Venus and Mars

The Outer Solar System

Meteorites, Asteroids, and Comets

Astrobiology: Life on Other Worlds

Filters

The pressure of an interstellar gas cloud depends on the cloud's and .

Ionization from the star in the Orion nebula makes it brightly.

The creation of ____ require(s) that a young hot star (T $\approx$ 25,000 K) be relatively nearby.