Question 1

Type M stars evolve to the main sequence faster than our G type Sun.

Accepted Answer

A) True 
 B)False

Question 2

Why does a star's luminosity drop so much during the Hayashi track?

Accepted Answer

The surface of the star maintains a fair...

Question 3

Why are brown dwarfs difficult to detect? Why have we had recent successes?

Accepted Answer

They are too cool to ignite nuclear fusi...

Question 4

How long does it take an O-type star to form,compared to the time for a solar-type star to form?

Accepted Answer

A)   1/300 as long
B)   1/30 as long
C)   about the same time
D)   30 times longer
E)   300 times longer

Question 5

Brown dwarfs are failed stars,never igniting their hydrogen fusion.

Accepted Answer

A) True 
 B)False

Question 6

Our Sun,along with most of the stars in our neighborhood,probably formed:

Accepted Answer

A)   a few million years ago.
B)   about 10 million years ago.
C)   hundreds of millions of years ago.
D)   billions of years ago.
E)   at the beginning of the universe.

Question 7

Higher mass protostars enter the main sequence:

Accepted Answer

A)   faster and at a higher luminosity and temperature.
B)   faster and at a lower luminosity and temperature.
C)   slower and at a higher luminosity and temperature.
D)   slower and at a lower luminosity and temperature.
E)   at the same rate, but at a higher luminosity and temperature.

Question 8

A protostar of 20 solar masses will probably turn into a type O main sequence star.

Accepted Answer

A) True 
 B)False

Question 9

Protostars can be observed in:

Accepted Answer

A)   the Crab Nebula.
B)   the Andromeda Galaxy.
C)   the Orion Nebula.
D)   our Solar System.
E)   the Helix Nebula.

Question 10

Which relationship concerning the mass of protostars is FALSE?

Accepted Answer

A)   The more massive ones will reach the main sequence first.
B)   The more massive ones will be the hottest and most luminous.
C)   The more massive ones one will be made of the heaviest elements.
D)   The more massive ones are so luminous they ionize the gas, hence red H II regions.
E)   The more massive ones create a lot of ultraviolet as well as visible light.

Question 11

During a protostar's T Tauri phase,it:

Accepted Answer

A)   begins a period of reduced activity.
B)   expands dramatically.
C)   lies on the main sequence.
D)   may develop very strong winds.
E)   changes its spin direction.

Question 12

Most stars are usually formed singularly or as binaries,not in clusters.

Accepted Answer

A) True 
 B)False

Question 13

Brown dwarfs are most easily detected which portion of the electromagnetic spectrum?

Accepted Answer

A)   X-ray
B)   ultraviolet
C)   visible light
D)   infrared
E)   radio

Question 14

At the end of the Kelvin-Helmholtz contraction a star is hundreds of times brighter than it will be as a main sequence star.

Accepted Answer

A) True 
 B)False

Question 15

Discuss the relationship between young stars and the interstellar medium.

Accepted Answer

Young stars give off ultraviolet radiati...

Question 16

What factors can complicate the collapse of an interstellar cloud into a star?

Accepted Answer

The initial spin of the cloud and the co...

Question 17

In the collapsing cloud fragment stage (stage 2) of star formation,the size of the cloud fragment is about:

Accepted Answer

A)   the size of the solar system.
B)   10 times the size of the solar system.
C)   100 times the size of the solar system.
D)   1,000 times the size of the solar system.
E)   10,000 times the size of the solar system.

Question 18

What is the key factor that determines the temperature,density,radius,luminosity,and pace of evolution of a protostellar object?

Accepted Answer

A)   composition of the nebula
B)   rotation of the nebula
C)   mass of the nebula
D)   temperature of the nebula
E)   magnetism of the nebula

Question 19

How long does it take for a star like our Sun to form?

Accepted Answer

A)   100 thousand years
B)   two million years
C)   fifty million years
D)   one billion years
E)   4.6 billion years

Question 20

What makes the subject of star formation so difficult and complex?

Accepted Answer

A)   It is so slow that no visible proof of it exists.
B)   Star formation is too expensive to study in detail.
C)   Stars live too long to be observed from birth to death.
D)   Clouds, fragments, protostars, stars, and nebulae all interact and influence each other.
E)   Shock waves disrupt the orderly evolution of stars.

Exam 19: Star Formation: A Traumatic Birth

What factors can complicate the collapse of an interstellar cloud into a star?

Correct AnswerverifiedThe initial spin of the cloud and the co...View AnswerShow Answer

Type M stars evolve to the main sequence faster than our G type Sun.

Correct AnswerverifiedShow Answer

Which relationship concerning the mass of protostars is FALSE?

Correct AnswerverifiedShow Answer

Brown dwarfs are most easily detected which portion of the electromagnetic spectrum?

Correct AnswerverifiedShow Answer

Why does a star's luminosity drop so much during the Hayashi track?

Correct AnswerverifiedThe surface of the star maintains a fair...View AnswerShow Answer

Our Sun,along with most of the stars in our neighborhood,probably formed:

Correct AnswerverifiedShow Answer

Protostars can be observed in:

Correct AnswerverifiedShow Answer

Discuss the relationship between young stars and the interstellar medium.

Correct AnswerverifiedYoung stars give off ultraviolet radiati...View AnswerShow Answer

Why are brown dwarfs difficult to detect? Why have we had recent successes?

Correct AnswerverifiedThey are too cool to ignite nuclear fusi...View AnswerShow Answer

Higher mass protostars enter the main sequence:

Correct AnswerverifiedShow Answer

What makes the subject of star formation so difficult and complex?

Correct AnswerverifiedShow Answer

A protostar of 20 solar masses will probably turn into a type O main sequence star.

Correct AnswerverifiedShow Answer

Most stars are usually formed singularly or as binaries,not in clusters.

Correct AnswerverifiedShow Answer

In the collapsing cloud fragment stage (stage 2) of star formation,the size of the cloud fragment is about:

Correct AnswerverifiedShow Answer

How long does it take for a star like our Sun to form?

Correct AnswerverifiedShow Answer

At the end of the Kelvin-Helmholtz contraction a star is hundreds of times brighter than it will be as a main sequence star.

Correct AnswerverifiedShow Answer

What is the key factor that determines the temperature,density,radius,luminosity,and pace of evolution of a protostellar object?

Correct AnswerverifiedShow Answer

How long does it take an O-type star to form,compared to the time for a solar-type star to form?

Correct AnswerverifiedShow Answer

During a protostar's T Tauri phase,it:

Correct AnswerverifiedShow Answer

Brown dwarfs are failed stars,never igniting their hydrogen fusion.

Correct AnswerverifiedShow Answer

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The initial spin of the cloud and the co...
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The surface of the star maintains a fair...
View Answer

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Young stars give off ultraviolet radiati...
View Answer

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They are too cool to ignite nuclear fusi...
View Answer

Correct Answer
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