Question 1

Pre-main-sequence stars (not protostars) on the H-R diagram are _____.

Accepted Answer

A)  above and to the right of supergiants 
B)  below and to the left of the main sequence 
C)  below and to the left of white dwarfs 
D)  above and to the right of the main sequence 
E)  not on the H-R diagram yet 
A)  above and to the right of supergiants 
B)  below and to the left of the main sequence 
C)  below and to the left of white dwarfs 
D)  above and to the right of the main sequence 
E)  not on the H-R diagram yet D

Question 2

The ISM magnetic field is typically about 0.0001 times as strong as Earth's magnetic field at its surface.

Accepted Answer

A) True 
 B)False  True

Question 3

The temperature at the core of a star must be at least 1 million degrees Kelvin before fusion can begin.

Accepted Answer

A) True 
 B)False  False

Question 4

A protostar will continue to collapse due to gravity until it reaches the main sequence, and then gravitational collapse will stop when _____ begins.

Accepted Answer

A)  the formation of star-globulars 
B)  atoms degenerate at the core of the star 
C)  the fusion of hydrogen 
D)  the fusion of helium 
E)  the fission of hydrogen 
A)  the formation of star-globulars 
B)  atoms degenerate at the core of the star 
C)  the fusion of hydrogen 
D)  the fusion of helium 
E)  the fission of hydrogen

Question 5

Columns of gas in a nebula that point back toward a young, massive star are called _______________.

Accepted Answer

star-forma

Question 6

As the protostar contracts gravitationally, it will rotate faster and faster and produce a(n) ____.

Accepted Answer

A)  protostellar globular 
B)  young stellar object (YSO) 
C)  protostellar envelope 
D)  cocoon nebula 
E)  protostellar disk 
A)  protostellar globular 
B)  young stellar object (YSO) 
C)  protostellar envelope 
D)  cocoon nebula 
E)  protostellar disk

Question 7

There are several triggers that could start the gravitational contraction of a molecular cloud and subsequent star formation.  List two of these triggers.

Accepted Answer

Shock waves can trigger star formation a

Question 8

The force responsible for the collapse of an interstellar cloud is_____________.

Accepted Answer

The answer of The force responsible for the collapse of...

Question 9

Low-mass stars like the Sun transport energy near their surface using convection.

Accepted Answer

A) True 
 B)False

Question 10

Eighty percent of the stars on the H-R diagram are on the main sequence, and that is because the star is in hydrostatic equilibrium due to the _____.

Accepted Answer

A)  degenerate property of hydrogen 
B)  degenerate property of helium 
C)  Hertzsprung-Russell principle 
D)  fusion of hydrogen 
E)  fusion of helium 
A)  degenerate property of hydrogen 
B)  degenerate property of helium 
C)  Hertzsprung-Russell principle 
D)  fusion of hydrogen 
E)  fusion of helium

Question 11

One trigger that could start the gravitational contraction of a molecular cloud to form stars is a passing shock wave.

Accepted Answer

A) True 
 B)False

Question 12

Convection is important in stars because it transports energy outward in the star.

Accepted Answer

A) True 
 B)False

Question 13

Hydrostatic equilibrium in a newborn star is regulated by a very unique thermostat called the _____________ thermostat.

Accepted Answer

pressure-t

Question 14

After a protostar has progressed in its development, it will have a dense inner part and an outer envelope called a(n) ____.

Accepted Answer

A)  outer-protostar 
B)  Bok globules 
C)  upper proto-sphere 
D)  cocoon nebulae 
E)  planetary nebulae 
A)  outer-protostar 
B)  Bok globules 
C)  upper proto-sphere 
D)  cocoon nebulae 
E)  planetary nebulae

Question 15

Before a giant molecular cloud can contract gravitationally, it must overcome four physical factors that resist compression.  What are these four factors?

Accepted Answer

1) The thermal energy of the g

Question 16

Our Sun took about ________ years from the collapse of its parent molecular cloud to become a main-sequence star.

Accepted Answer

A)  30 
B)  30,000 
C)  5 million 
D)  30 million 
E)  1 billion 
A)  30 
B)  30,000 
C)  5 million 
D)  30 million 
E)  1 billion

Question 17

The Sun, a one-solar-mass star, will take approximately how many years to go from protostar to main-sequence star?

Accepted Answer

A)  160,000 years 
B)  700,000 years 
C)  8 million years 
D)  30 million years 
E)  100 million years 
A)  160,000 years 
B)  700,000 years 
C)  8 million years 
D)  30 million years 
E)  100 million years

Question 18

Main sequence O stars have convective cores because they fuse hydrogen in the proton-proton chain.

Accepted Answer

A) True 
 B)False

Question 19

T Tauri stars are understood to be relatively low-mass __________.

Accepted Answer

A)  dust cocoons 
B)  protostars 
C)  Herbig-Haro objects 
D)  nebulae 
E)  associations 
A)  dust cocoons 
B)  protostars 
C)  Herbig-Haro objects 
D)  nebulae 
E)  associations

Question 20

What is the resistance of a gas to the flow of radiation?

Accepted Answer

A)  degeneracy 
B)  conduction 
C)  opacity 
D)  hydrostatic pressure 
E)  gravitational pressure 
A)  degeneracy 
B)  conduction 
C)  opacity 
D)  hydrostatic pressure 
E)  gravitational pressure

Pre-main-sequence stars (not protostars) on the H-R diagram are _____.

The ISM magnetic field is typically about 0.0001 times as strong as Earth's magnetic field at its surface.

The temperature at the core of a star must be at least 1 million degrees Kelvin before fusion can begin.

A protostar will continue to collapse due to gravity until it reaches the main sequence, and then gravitational collapse will stop when _____ begins.

Columns of gas in a nebula that point back toward a young, massive star are called _______________.

As the protostar contracts gravitationally, it will rotate faster and faster and produce a(n) ____.

There are several triggers that could start the gravitational contraction of a molecular cloud and subsequent star formation. List two of these triggers.

The force responsible for the collapse of an interstellar cloud is_____________.

Low-mass stars like the Sun transport energy near their surface using convection.

Eighty percent of the stars on the H-R diagram are on the main sequence, and that is because the star is in hydrostatic equilibrium due to the _____.

One trigger that could start the gravitational contraction of a molecular cloud to form stars is a passing shock wave.

Convection is important in stars because it transports energy outward in the star.

Hydrostatic equilibrium in a newborn star is regulated by a very unique thermostat called the _____________ thermostat.

After a protostar has progressed in its development, it will have a dense inner part and an outer envelope called a(n) ____.

Before a giant molecular cloud can contract gravitationally, it must overcome four physical factors that resist compression. What are these four factors?

Our Sun took about ________ years from the collapse of its parent molecular cloud to become a main-sequence star.

The Sun, a one-solar-mass star, will take approximately how many years to go from protostar to main-sequence star?

Main sequence O stars have convective cores because they fuse hydrogen in the proton-proton chain.

T Tauri stars are understood to be relatively low-mass __________.

What is the resistance of a gas to the flow of radiation?

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Origins of Modern Astronomy

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Exam 11: Formation and Structure of Stars

Pre-main-sequence stars (not protostars) on the H-R diagram are _____.

The ISM magnetic field is typically about 0.0001 times as strong as Earth's magnetic field at its surface.

The temperature at the core of a star must be at least 1 million degrees Kelvin before fusion can begin.

A protostar will continue to collapse due to gravity until it reaches the main sequence, and then gravitational collapse will stop when _____ begins.

Columns of gas in a nebula that point back toward a young, massive star are called _______________.

As the protostar contracts gravitationally, it will rotate faster and faster and produce a(n) ____.

There are several triggers that could start the gravitational contraction of a molecular cloud and subsequent star formation. List two of these triggers.

The force responsible for the collapse of an interstellar cloud is_____________.

Low-mass stars like the Sun transport energy near their surface using convection.

Eighty percent of the stars on the H-R diagram are on the main sequence, and that is because the star is in hydrostatic equilibrium due to the _____.

One trigger that could start the gravitational contraction of a molecular cloud to form stars is a passing shock wave.

Convection is important in stars because it transports energy outward in the star.

Hydrostatic equilibrium in a newborn star is regulated by a very unique thermostat called the _____________ thermostat.

After a protostar has progressed in its development, it will have a dense inner part and an outer envelope called a(n) ____.

Before a giant molecular cloud can contract gravitationally, it must overcome four physical factors that resist compression. What are these four factors?

Our Sun took about ________ years from the collapse of its parent molecular cloud to become a main-sequence star.

The Sun, a one-solar-mass star, will take approximately how many years to go from protostar to main-sequence star?

Main sequence O stars have convective cores because they fuse hydrogen in the proton-proton chain.

T Tauri stars are understood to be relatively low-mass __________.

What is the resistance of a gas to the flow of radiation?

Here and Now

A Users Guide to the Sky

Moon Phases and Eclipses

Origins of Modern Astronomy

Gravity

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Interstellar Medium

Stellar Evolution

Deaths of Stars

Neutron Stars and Black Holes

The Milky Way Galaxy

Galaxies

Supermassive Black Holes and Active Galaxies

Modern Cosmology

Astrobiology

Filters