Question 1

As a molecular cloud core collapses,what can we expect to occur?

Accepted Answer

A) The rotation rate increases,which inhibits the formation of a disk. 
B) The rotation rate decreases,which inhibits the formation of a disk. 
C) The rotation rate increases,which enhances the formation of a disk. 
D) The rotation rate decreases,which enhances the formation of a disk. 
A) The rotation rate increases,which inhibits the formation of a disk. 
B) The rotation rate decreases,which inhibits the formation of a disk. 
C) The rotation rate increases,which enhances the formation of a disk. 
D) The rotation rate decreases,which enhances the formation of a disk. A

Question 2

Which of the following clusters is the youngest?

Accepted Answer

A) Its least massive stars are just arriving on the main sequence 
B) Its most massive stars are just arriving on the main sequence 
C) Its least massive stars are just leaving the main sequence 
D) Its most massive stars are just leaving the main sequence 
A) Its least massive stars are just arriving on the main sequence 
B) Its most massive stars are just arriving on the main sequence 
C) Its least massive stars are just leaving the main sequence 
D) Its most massive stars are just leaving the main sequence B

Question 3

Where are very young stars located in an H-R diagram?

Accepted Answer

A) Above and to the right of the main sequence 
B) Lower left 
C) Below the main sequence 
D) In the upper left 
A) Above and to the right of the main sequence 
B) Lower left 
C) Below the main sequence 
D) In the upper left A

Question 4

Which of the following is not easily accounted for in current versions of the nebular theory of the origin of the solar system?

Accepted Answer

A) The Sun's equator lies nearly in the ecliptic 
B) Planet-satellite systems resemble the solar system 
C) The rotation of Venus 
D) The planets orbit the Sun in the same direction 
A) The Sun's equator lies nearly in the ecliptic 
B) Planet-satellite systems resemble the solar system 
C) The rotation of Venus 
D) The planets orbit the Sun in the same direction

Question 5

An HR diagram is a plot of:

Accepted Answer

A) amplitude verses pressure. 
B) luminosity verses surface temperature. 
C) mass verses brightness. 
D) pressure verses surface temperature. 
A) amplitude verses pressure. 
B) luminosity verses surface temperature. 
C) mass verses brightness. 
D) pressure verses surface temperature.

Question 6

If nebular theories of the origin of the solar system are correct,then which of the following is a likely consequence?

Accepted Answer

A) There are many planetary systems in the galaxy 
B) The Sun is much older than the planets 
C) Fusion is not occurring in the Sun 
D) The Sun once had a binary companion 
A) There are many planetary systems in the galaxy 
B) The Sun is much older than the planets 
C) Fusion is not occurring in the Sun 
D) The Sun once had a binary companion

Question 7

Which of the following is an example of a newborn star?

Accepted Answer

A) An asymptotic giant branch star 
B) A reflection nebula 
C) A T Tauri star 
D) A pulsar 
A) An asymptotic giant branch star 
B) A reflection nebula 
C) A T Tauri star 
D) A pulsar

Question 8

The H-R diagram of a cluster shows that the least massive stars lie above the main sequence (that is they are more luminous than main sequence stars).What can we conclude about the cluster?

Accepted Answer

A) It has an unusual chemical composition 
B) Its least massive stars are more massive than the stars near the Sun 
C) It is quite young 
D) Its stars have large magnetic fields 
A) It has an unusual chemical composition 
B) Its least massive stars are more massive than the stars near the Sun 
C) It is quite young 
D) Its stars have large magnetic fields

Question 9

The solar system

Accepted Answer

A) Took several billion years to form 
B) Underwent several intervals of planet formation separated by billions of years 
C) Formed about 5 million years ago 
D) Reached more or less its present form in less than a billion years 
A) Took several billion years to form 
B) Underwent several intervals of planet formation separated by billions of years 
C) Formed about 5 million years ago 
D) Reached more or less its present form in less than a billion years

Question 10

What happened to the gas that was left over in the solar nebula after the planets formed?

Accepted Answer

A) It was blown away by a strong wind 
B) It fell back into the Sun 
C) It was swept away by a passing star 
D) It condensed to form the zodiacal light 
A) It was blown away by a strong wind 
B) It fell back into the Sun 
C) It was swept away by a passing star 
D) It condensed to form the zodiacal light

Question 11

As an interstellar cloud collapses to become a star,its central region eventually becomes opaque.Why is this a significant development in the formation of the star?

Accepted Answer

A) Temperature can now begin to rise 
B) The star now begins to rotate 
C) The star now begins to radiate infrared radiation 
D) Magnetic pressure now prevents further collapse 
A) Temperature can now begin to rise 
B) The star now begins to rotate 
C) The star now begins to radiate infrared radiation 
D) Magnetic pressure now prevents further collapse

Question 12

What were planetesimals?

Accepted Answer

A) Interplanetary grains 
B) Bodies,as massive as the Earth,that formed the cores of the giant planets 
C) Intermediate-size bodies that combined with others to form planets 
D) Interstellar bodies captured by the Sun soon after it formed 
A) Interplanetary grains 
B) Bodies,as massive as the Earth,that formed the cores of the giant planets 
C) Intermediate-size bodies that combined with others to form planets 
D) Interstellar bodies captured by the Sun soon after it formed

Question 13

What process is responsible for the formation of a new star?

Accepted Answer

A) The collision of one or more stars 
B) The collapse of part of a cloud of interstellar material 
C) The gathering of material around a black hole 
D) The collision of massive planets in interstellar space 
A) The collision of one or more stars 
B) The collapse of part of a cloud of interstellar material 
C) The gathering of material around a black hole 
D) The collision of massive planets in interstellar space

Question 14

The contraction of a gaseous cloud out of which a star and a planetary system form is caused by what kind of force?

Accepted Answer

A) Electric 
B) Nuclear 
C) Magnetic 
D) Gravitational 
A) Electric 
B) Nuclear 
C) Magnetic 
D) Gravitational

Question 15

According to nebular theories,the planets formed from material that was

Accepted Answer

A) Pulled from the Sun during a collision with another star 
B) Ejected from the Sun by an explosion 
C) Captured by the Sun from interstellar space 
D) Part of the collapsing cloud that formed the Sun 
A) Pulled from the Sun during a collision with another star 
B) Ejected from the Sun by an explosion 
C) Captured by the Sun from interstellar space 
D) Part of the collapsing cloud that formed the Sun

Question 16

As an interstellar cloud collapses to become a star,its central parts at first heat up very slowly.Why?

Accepted Answer

A) Infrared radiation can escape and cool the cloud 
B) The collapse is too slow to generate much energy 
C) Any heated atoms escape from the collapsing cloud 
D) The core of the cloud is degenerate 
A) Infrared radiation can escape and cool the cloud 
B) The collapse is too slow to generate much energy 
C) Any heated atoms escape from the collapsing cloud 
D) The core of the cloud is degenerate

Question 17

Which of the following is a serious objection to catastrophic theories of the origin of the solar system?

Accepted Answer

A) Collisions between stars are rare events 
B) The planets are much younger than the Sun 
C) Material pulled from the Sun would have been too hot to form planets 
D) A separate collision would have been needed to form each planet 
A) Collisions between stars are rare events 
B) The planets are much younger than the Sun 
C) Material pulled from the Sun would have been too hot to form planets 
D) A separate collision would have been needed to form each planet

Question 18

Why do the H-R diagrams of young clusters show the least massive stars located above the zero-age main sequence?

Accepted Answer

A) They are always the first stars to form in a cluster 
B) They take longer to reach the main sequence 
C) They evolve away from the main sequence before more massive stars do 
D) They are actually binaries,and thus seem overluminous 
A) They are always the first stars to form in a cluster 
B) They take longer to reach the main sequence 
C) They evolve away from the main sequence before more massive stars do 
D) They are actually binaries,and thus seem overluminous

Question 19

The core of a proto-star remains relatively cool until which of the following happens?

Accepted Answer

A) The star becomes opaque 
B) Nuclear reactions begin 
C) The chemical composition of the star changes 
D) Its spin slows significantly 
A) The star becomes opaque 
B) Nuclear reactions begin 
C) The chemical composition of the star changes 
D) Its spin slows significantly

Question 20

What is the evolutionary status of a T Tauri star?

Accepted Answer

A) Main sequence star 
B) Newborn star 
C) Red giant 
D) Old pulsar 
A) Main sequence star 
B) Newborn star 
C) Red giant 
D) Old pulsar

Exam 18: The Formation of Stars and Planets

As a molecular cloud core collapses,what can we expect to occur?

Which of the following clusters is the youngest?

Where are very young stars located in an H-R diagram?

Which of the following is not easily accounted for in current versions of the nebular theory of the origin of the solar system?

An HR diagram is a plot of:

If nebular theories of the origin of the solar system are correct,then which of the following is a likely consequence?

Which of the following is an example of a newborn star?

The H-R diagram of a cluster shows that the least massive stars lie above the main sequence (that is they are more luminous than main sequence stars).What can we conclude about the cluster?

The solar system

What happened to the gas that was left over in the solar nebula after the planets formed?

As an interstellar cloud collapses to become a star,its central region eventually becomes opaque.Why is this a significant development in the formation of the star?

What were planetesimals?

What process is responsible for the formation of a new star?

The contraction of a gaseous cloud out of which a star and a planetary system form is caused by what kind of force?

According to nebular theories,the planets formed from material that was

As an interstellar cloud collapses to become a star,its central parts at first heat up very slowly.Why?

Which of the following is a serious objection to catastrophic theories of the origin of the solar system?

Why do the H-R diagrams of young clusters show the least massive stars located above the zero-age main sequence?

The core of a proto-star remains relatively cool until which of the following happens?

What is the evolutionary status of a T Tauri star?

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