Question 1

The Sun makes most of its energy by the CNO cycle.

Accepted Answer

A) True 
 B)False

Question 2

If a star's pressure increases in its interior to push the star outward, its temperature will drop, causing the star to contract and eventually return to equilibrium.

Accepted Answer

A) True 
 B)False

Question 3

The carbon-nitrogen-oxygen cycle

Accepted Answer

A)  operates at a slightly lower temperature than the proton-proton chain. 
B)  is most efficient in star less massive than the Sun. 
C)  occurs when carbon and oxygen combine to form nitrogen, which produces energy. 
D)  produces the energy responsible for bipolar flows. 
E)  combines four hydrogen nuclei to form one helium nucleus, which produces energy. 
A)  operates at a slightly lower temperature than the proton-proton chain. 
B)  is most efficient in star less massive than the Sun. 
C)  occurs when carbon and oxygen combine to form nitrogen, which produces energy. 
D)  produces the energy responsible for bipolar flows. 
E)  combines four hydrogen nuclei to form one helium nucleus, which produces energy.

Question 4

The CNO cycle requires higher temperatures than those needed in the proton-proton fusion chain.

Accepted Answer

A) True 
 B)False

Question 5

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. 
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.

Question 6

________ occurs when most of the material collapsing to form a protostar has fallen into a disk around the star and a strong wind from the warm protostar ejects material from its poles.

Accepted Answer

A)  An emission nebula 
B)  Hydrostatic equilibrium 
C)  The proton-proton chain 
D)  The thermonuclear fusion of hydrogen 
E)  A bipolar outflow 
A)  An emission nebula 
B)  Hydrostatic equilibrium 
C)  The proton-proton chain 
D)  The thermonuclear fusion of hydrogen 
E)  A bipolar outflow

Question 7

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

Accepted Answer

temperatur

Question 8

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 9

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 lifetimes 
A)  0.5 solar lifetimes 
B)  1 solar lifetime 
C)  2 solar lifetimes 
D)  10 solar lifetimes

Question 10

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 contract 
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 contract

Question 11

How does a gas cloud become hot?

Accepted Answer

Once the gas cloud begins to contract, g

Question 12

Stars are born in ______________________.

Accepted Answer

A)  molecular clouds 
B)  atomic hydrogen clouds 
C)  emission nebula 
D)  reflection nebula 
A)  molecular clouds 
B)  atomic hydrogen clouds 
C)  emission nebula 
D)  reflection nebula

Question 13

In the above image, the forming star is clearly seen.

Accepted Answer

A) True 
 B)False

Question 14

In the above 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 lines 
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 lines

Question 15

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 16

Why are reflection nebulae blue in color?

Accepted Answer

Reflection nebulae look blue for the sam

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

How long a star can stay on the main sequence depends upon its size.

Accepted Answer

A) True 
 B)False

Question 19

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

Accepted Answer

High-speed collisions between atoms and

Question 20

T Tauri stars are in hydrostatic equilibrium.

Accepted Answer

A) True 
 B)False

The Sun makes most of its energy by the CNO cycle.

If a star's pressure increases in its interior to push the star outward, its temperature will drop, causing the star to contract and eventually return to equilibrium.

The carbon-nitrogen-oxygen cycle

The CNO cycle requires higher temperatures than those needed in the proton-proton fusion chain.

Absorption lines due to interstellar gas

________ occurs when most of the material collapsing to form a protostar has fallen into a disk around the star and a strong wind from the warm protostar ejects material from its poles.

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

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?

How long can a 1-solar-mass star live?

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

How does a gas cloud become hot?

Stars are born in ______________________.

In the above image, the forming star is clearly seen.

In the above cartoon image of Orion, where would you find the Orion nebula?

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

Why are reflection nebulae blue in color?

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

How long a star can stay on the main sequence depends upon its size.

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

T Tauri stars are in hydrostatic equilibrium.

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

Origin of the Solar System and Extrasolar Planets

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

Exam 9: The Formation and Structure of Stars

The Sun makes most of its energy by the CNO cycle.

If a star's pressure increases in its interior to push the star outward, its temperature will drop, causing the star to contract and eventually return to equilibrium.

The carbon-nitrogen-oxygen cycle

The CNO cycle requires higher temperatures than those needed in the proton-proton fusion chain.

Absorption lines due to interstellar gas

________ occurs when most of the material collapsing to form a protostar has fallen into a disk around the star and a strong wind from the warm protostar ejects material from its poles.

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

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?

How long can a 1-solar-mass star live?

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

How does a gas cloud become hot?

Stars are born in ______________________.

In the above image, the forming star is clearly seen.

In the above cartoon image of Orion, where would you find the Orion nebula?

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

Why are reflection nebulae blue in color?

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

How long a star can stay on the main sequence depends upon its size.

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

T Tauri stars are in hydrostatic equilibrium.

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

Origin of the Solar System and Extrasolar Planets

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 .

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