Question 1

What is the key factor that determines the temperature, density, radius, luminosity, and paceof 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 
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 2

While a star develops from a protostar to a main sequence star, a higher mass star'sevolutionary track, compared to the evolutionary track of a lower mass star:

Accepted Answer

A) shows that the high mass protostar forms into a star at the same location on the mainsequence. 
B) shows that the high mass protostar forms into a redder star on the main sequence. 
C) shows that the high mass protostar forms into a bluer star on the main sequence. 
D) shows that the evolutionary track of these stars cross as they develop into a main sequencestar. 
E) tells us nothing about the main sequence star that will form. 
A) shows that the high mass protostar forms into a star at the same location on the mainsequence. 
B) shows that the high mass protostar forms into a redder star on the main sequence. 
C) shows that the high mass protostar forms into a bluer star on the main sequence. 
D) shows that the evolutionary track of these stars cross as they develop into a main sequencestar. 
E) tells us nothing about the main sequence star that will form.

Question 3

During the Hayashi track, a star drops drastically in both ________ and ________.

Accepted Answer

The answer of During the Hayashi track, a star drops...

Question 4

In the collapsing cloud fragment stage (stage 2)of star formation, the size of the cloudfragment 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. 
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 5

If a star is spinning rapidly, this may limit its final mass.

Accepted Answer

A) True 
 B)False

Question 6

Whether an object is a brown dwarf or a planet can be determined by:

Accepted Answer

A) the mass of the object. 
B) the temperature of the object. 
C) the composition of the object. 
D) the diameter of the object. 
E) whether the object is inside or outside of the galaxy. 
A) the mass of the object. 
B) the temperature of the object. 
C) the composition of the object. 
D) the diameter of the object. 
E) whether the object is inside or outside of the galaxy.

Question 7

A stage 4 protostar may temporarily be thousands of times more luminous than the Sun.

Accepted Answer

A) True 
 B)False

Question 8

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

Accepted Answer

The surface of the star maintains a fair

Question 9

When a typical open cluster forms, which type of stars are formed most often?

Accepted Answer

A) solar type stars of class G 
B) OB associations 
C) red giants 
D) low mass M type dwarfs 
E) white dwarfs 
A) solar type stars of class G 
B) OB associations 
C) red giants 
D) low mass M type dwarfs 
E) white dwarfs

Question 10

If the initial interstellar cloud in star formation has a mass sufficient to form hundreds ofstars, how does a single star form from it?

Accepted Answer

A) One star forms at its center and blows the rest of the matter back into space. 
B) The cloud fragments into smaller clouds and forms many stars at one time. 
C) One star forms and the rest of the matter goes into making planets, moons, and other objectsof a solar system. 
D) The cloud is disrupted by rotation so that it reduces its mass down to that of a typical star. 
E) A supernova blows the cloud up and dissipates the majority of the gas. 
A) One star forms at its center and blows the rest of the matter back into space. 
B) The cloud fragments into smaller clouds and forms many stars at one time. 
C) One star forms and the rest of the matter goes into making planets, moons, and other objectsof a solar system. 
D) The cloud is disrupted by rotation so that it reduces its mass down to that of a typical star. 
E) A supernova blows the cloud up and dissipates the majority of the gas.

Question 11

What happens when an interstellar cloud fragment shrinks?

Accepted Answer

A) It first becomes opaque. 
B) Density rises. 
C) Temperature rises. 
D) Pressure rises. 
E) all of the above 
A) It first becomes opaque. 
B) Density rises. 
C) Temperature rises. 
D) Pressure rises. 
E) all of the above

Question 12

Since brown dwarfs cannot ignite hydrogen fusion, how might we hope to spot them? Whatrole does deuterium play in this?

Accepted Answer

In the Kelvin-Helmholtz contraction, the

Question 13

Atomic bomb tests demonstrated which aspect of star formation?

Accepted Answer

A) a shock wave surrounding and compressing a molecular cloud 
B) the ignition of fusion that changes a protostar to a star 
C) a protostar's movement on the Hayashi track 
D) the fragmentation of a molecular cloud 
E) a shock wave pushing a molecular cloud from one side 
A) a shock wave surrounding and compressing a molecular cloud 
B) the ignition of fusion that changes a protostar to a star 
C) a protostar's movement on the Hayashi track 
D) the fragmentation of a molecular cloud 
E) a shock wave pushing a molecular cloud from one side

Question 14

Explain how the composition of the object can help distinguish a brown dwarf from a planet.

Accepted Answer

Planets are enriched in heavy

Question 15

How are T Tauri stars characterized observationally?

Accepted Answer

A) by sudden changes in their brightness 
B) by very high temperatures 
C) by very high magnetic fields and large starspots 
D) by very rapid rotation 
E) They are newly formed stars that are short period binaries. 
A) by sudden changes in their brightness 
B) by very high temperatures 
C) by very high magnetic fields and large starspots 
D) by very rapid rotation 
E) They are newly formed stars that are short period binaries.

Question 16

What are some sources of the shock waves that initiate star formation?

Accepted Answer

Emission nebulae produce shock waves, re

Question 17

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

Accepted Answer

A) True 
 B)False

Question 18

What are the characteristics of globular cluster stars?

Accepted Answer

A) no stars as hot as our Sun 
B) old age and hundreds of thousands to millions of member stars 
C) no main sequence stars left, with billions of member stars 
D) a few hundred stars, most still on the main sequence 
E) hundreds of light-years across, with bright OB stars dominant 
A) no stars as hot as our Sun 
B) old age and hundreds of thousands to millions of member stars 
C) no main sequence stars left, with billions of member stars 
D) a few hundred stars, most still on the main sequence 
E) hundreds of light-years across, with bright OB stars dominant

Question 19

It takes about 1032 hydrogen atoms to make a star.

Accepted Answer

A) True 
 B)False

Question 20

In general, the greater the mass of the protostar, the ________ it contracts to the mainsequence.

Accepted Answer

The answer of In general, the greater the mass of...

Exam 19: Star Formation: a Traumatic Birth

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

While a star develops from a protostar to a main sequence star, a higher mass star'sevolutionary track, compared to the evolutionary track of a lower mass star:

During the Hayashi track, a star drops drastically in both ________ and ________.

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

If a star is spinning rapidly, this may limit its final mass.

Whether an object is a brown dwarf or a planet can be determined by:

A stage 4 protostar may temporarily be thousands of times more luminous than the Sun.

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

When a typical open cluster forms, which type of stars are formed most often?

If the initial interstellar cloud in star formation has a mass sufficient to form hundreds ofstars, how does a single star form from it?

What happens when an interstellar cloud fragment shrinks?

Since brown dwarfs cannot ignite hydrogen fusion, how might we hope to spot them? Whatrole does deuterium play in this?

Atomic bomb tests demonstrated which aspect of star formation?

Explain how the composition of the object can help distinguish a brown dwarf from a planet.

How are T Tauri stars characterized observationally?

What are some sources of the shock waves that initiate star formation?

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

What are the characteristics of globular cluster stars?

It takes about 1032 hydrogen atoms to make a star.

In general, the greater the mass of the protostar, the ________ it contracts to the mainsequence.

Charting the Heavens: The Foundations of Astronomy

The Copernican Revolution: The Birth of Modern Science

Radiation: Information From the Cosmos

Spectroscopy: the Inner Workings of Atoms

Telescopes: The Tools of Astronomy

The Solar System: Comparative Planetology and Formation Models

Earth: Our Home in Space

The Moon and Mercury: Scorched and Battered Worlds

Venus: Earths Sister Planet

Mars: a Near Miss for Life

Jupiter: Giant of the Solar System

Saturn: Spectacular Rings and Mysterious Moons

Uranus and Neptune: The Outer Worlds of the Solar System

Solar System Debris: Keys to Our Origin

Exoplanets: Planetary Systems Beyond Our Own

The Sun: Our Parent Star

The Stars: Giants, Dwarfs, and the Main Sequence

The Interstellar Medium: Gas and Dust Among the Stars

Stellar Evolution: The Life and Death of a Star

Stellar Explosions: Novae, Supernovae, and the Formation of the Elements

Neutron Stars and Black Holes: Strange States of Matter

The Milky Way Galaxy: a Spiral in Space

Galaxies: Building Blocks of the Universe

Galaxies and Dark Matter: The Large-Scale Structure of the Cosmos

Cosmology: The Big Bang and the Fate of the Universe

The Early Universe: Toward the Beginning of Time

Life in the Universe: Are We Alone

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During the Hayashi track, a star drops drastically in both and .