Question 1

T Tauri stars are in hydrostatic equilibrium.

Accepted Answer

A) True 
 B)False

Question 2

The Sun has a core in which energy travels outward primarily by radiation.

Accepted Answer

A) True 
 B)False

Question 3

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

Accepted Answer

The proton-proton chain occurs at temper

Question 4

The interstellar medium is made of ___ % dust and ___ % gas.

Accepted Answer

A) 1, 99 
B) 0, 100 
C) 100, 0 
D) 5, 95 
A) 1, 99 
B) 0, 100 
C) 100, 0 
D) 5, 95

Question 5

The H-R diagram main-sequence of stars has a limit at the lower-mass or energy-output end because

Accepted Answer

A) low-mass stars form from the interstellar medium very rarely. 
B) low-mass objects are composed primarily of solids, not gases. 
C) pressure does not depend on temperature in degenerate matter. 
D) the lower limit represents when the radius of the star would be zero. 
E) there is a minimum temperature for hydrogen nuclear fusion (the definition of a star). 
A) low-mass stars form from the interstellar medium very rarely. 
B) low-mass objects are composed primarily of solids, not gases. 
C) pressure does not depend on temperature in degenerate matter. 
D) the lower limit represents when the radius of the star would be zero. 
E) there is a minimum temperature for hydrogen nuclear fusion (the definition of a star).

Question 6

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

Accepted Answer

A) True 
 B)False

Question 7

What is the lifetime of a 10-solar-mass star on the main sequence

Accepted Answer

A) $3.2 × 10^7$ years 
B) 320 years 
C) $3.2 × 10^{12}$ years 
D) $1× 10^9$ years 
E) $1 × 10^{11}$ years 
A) $3.2 × 10^7$ years 
B) 320 years 
C) $3.2 × 10^{12}$ years 
D) $1× 10^9$ years 
E) $1 × 10^{11}$ years

Question 8

Opacity is

Accepted Answer

A) the balance between the pressure and force of gravity inside a star. 
B) the force that binds protons and neutrons together to form a nucleus. 
C) the force that binds an electron to the nucleus in an atom. 
D) a measure of the resistance to the flow of radiation (photons) through a gas. 
E) the temperature and density at which a gas will undergo thermonuclear fusion. 
A) the balance between the pressure and force of gravity inside a star. 
B) the force that binds protons and neutrons together to form a nucleus. 
C) the force that binds an electron to the nucleus in an atom. 
D) a measure of the resistance to the flow of radiation (photons) through a gas. 
E) the temperature and density at which a gas will undergo thermonuclear fusion.

Question 9

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 10

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 11

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 12

Why is a brown dwarf not considered a star

Accepted Answer

A brown dwarf is an object wit

Question 13

If in a gas the opacity is high, then energy transport is by _____________.

Accepted Answer

A) conduction 
B) convection 
C) radiation 
D) All of the other choices are correct. 
A) conduction 
B) convection 
C) radiation 
D) All of the other choices are correct.

Question 14

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

Accepted Answer

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

Question 15

As a star begin to form the initial energy source is 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 16

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 17

Convection is important in stars because it

Accepted Answer

A) increases the temperature of the star. 
B) mixes the gases of the star. 
C) transports energy outward in the star. 
D) carries the neutrinos to the surface of the star where they can escape. 
E) mixes the gases of the star and transports the energy outward in the star. 
A) increases the temperature of the star. 
B) mixes the gases of the star. 
C) transports energy outward in the star. 
D) carries the neutrinos to the surface of the star where they can escape. 
E) mixes the gases of the star and transports the energy outward in the star.

Question 18

The Orion region contains young main-sequence stars and an emission nebula, but the original molecular cloud they formed out of has been dispersed.

Accepted Answer

A) True 
 B)False

Question 19

-The above visual wavelength image is of a ___________, which is a(n) _________.

Accepted Answer

A) dark nebula, empty space 
B) reflection nebula, dark cloud 
C) Bok globule, empty space 
D) emission nebula, dark cloud 
A) dark nebula, empty space 
B) reflection nebula, dark cloud 
C) Bok globule, empty space 
D) emission nebula, dark cloud

Question 20

You would like to see through the dust in a cloud to find protostars. Which band of the electromagnetic spectrum would you need to look in

Accepted Answer

A) infrared 
B) visual 
C) UV 
D) X-ray 
A) infrared 
B) visual 
C) UV 
D) X-ray

T Tauri stars are in hydrostatic equilibrium.

The Sun has a core in which energy travels outward primarily by radiation.

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

The interstellar medium is made of _ % dust and _ % gas.

The H-R diagram main-sequence of stars has a limit at the lower-mass or energy-output end because

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

What is the lifetime of a 10-solar-mass star on the main sequence

Opacity is

The carbon-nitrogen-oxygen cycle

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

The H-R diagram of a young star cluster shows

Why is a brown dwarf not considered a star

If in a gas the opacity is high, then energy transport is by _____________.

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

As a star begin to form the initial energy source is from

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

Convection is important in stars because it

The Orion region contains young main-sequence stars and an emission nebula, but the original molecular cloud they formed out of has been dispersed.

-The above visual wavelength image is of a ___, which is a(n) _.

You would like to see through the dust in a cloud to find protostars. Which band of the electromagnetic spectrum would you need to look in

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

Exam 9: The Formation and Structure of Stars

T Tauri stars are in hydrostatic equilibrium.

The Sun has a core in which energy travels outward primarily by radiation.

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

The interstellar medium is made of ___ % dust and ___ % gas.

The H-R diagram main-sequence of stars has a limit at the lower-mass or energy-output end because

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

What is the lifetime of a 10-solar-mass star on the main sequence

Opacity is

The carbon-nitrogen-oxygen cycle

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

The H-R diagram of a young star cluster shows

Why is a brown dwarf not considered a star

If in a gas the opacity is high, then energy transport is by _____________.

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

As a star begin to form the initial energy source is from

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

Convection is important in stars because it

The Orion region contains young main-sequence stars and an emission nebula, but the original molecular cloud they formed out of has been dispersed.

-The above visual wavelength image is of a ___________, which is a(n) _________.

You would like to see through the dust in a cloud to find protostars. Which band of the electromagnetic spectrum would you need to look in

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 interstellar medium is made of _ % dust and _ % gas.

-The above visual wavelength image is of a ___, which is a(n) _.