Question 1

What star is the most likely to have made the atoms of gold in your jewelry or your electronics?

Accepted Answer

A) the Sun 
B) a white dwarf 
C) a low- mass star 
D) a high- mass star 
A) the Sun 
B) a white dwarf 
C) a low- mass star 
D) a high- mass star

Question 2

Which of the following statements about brown dwarfs is not true?

Accepted Answer

A) Brown dwarfs are supported against gravity by degeneracy pressure, which does not depend on the object's temperature. 
B) Brown dwarfs form like ordinary stars but are too small to sustain nuclear fusion in their cores. 
C) All brown dwarfs have masses less than about 8% that of our Sun. 
D) Brown dwarfs eventually collapse to become white dwarfs. 
A) Brown dwarfs are supported against gravity by degeneracy pressure, which does not depend on the object's temperature. 
B) Brown dwarfs form like ordinary stars but are too small to sustain nuclear fusion in their cores. 
C) All brown dwarfs have masses less than about 8% that of our Sun. 
D) Brown dwarfs eventually collapse to become white dwarfs.

Question 3

The Faintest White Dwarfs: All low- mass stars end their lives by forming white dwarfs which evolve by cooling at a constant radius, growing less and less luminous with time. You are about to begin an observing program to look for the faintest white dwarfs in the Milky Way Galaxy. In the course of your observations, will you continue to find white dwarfs that are less and less luminous, or will you ultimately find a population of white dwarfs that are the least luminous ones in the Milky Way? If you answer the latter, what is your interpretation of this result?

Accepted Answer

In the course of our observations, we wi

Question 4

Do you think it is possible that a 10- solar- mass main- sequence star could harbor an advanced civilization? Explain your reasoning.

Accepted Answer

A 10- solar- mass star has a v

Question 5

Our Sun will end its life in a planetary nebula and become a white dwarf.

Accepted Answer

A) True 
 B)False

Question 6

What is a planetary nebula?

Accepted Answer

A) gas created from the remains of planets that once orbited a dead star 
B) gas ejected from a low- mass star in the final stage of its life 
C) the remains of a high- mass star that has exploded 
D) interstellar gas from which planets are likely to form in the not- too- distant future 
A) gas created from the remains of planets that once orbited a dead star 
B) gas ejected from a low- mass star in the final stage of its life 
C) the remains of a high- mass star that has exploded 
D) interstellar gas from which planets are likely to form in the not- too- distant future

Question 7

Which part of the electromagnetic spectrum generally gives us our best views of stars forming in dusty clouds?

Accepted Answer

A) visible light 
B) infrared 
C) blue light 
D) ultraviolet 
A) visible light 
B) infrared 
C) blue light 
D) ultraviolet

Question 8

What happens when the gravity of a massive star is able to overcome neutron degeneracy pressure?

Accepted Answer

A) The core contracts and becomes a black hole. 
B) The star explodes violently, leaving nothing behind. 
C) The core contracts and becomes a ball of neutrons. 
D) Gravity is not able to overcome neutron degeneracy pressure. 
E) The core contracts and becomes a white dwarf. 
A) The core contracts and becomes a black hole. 
B) The star explodes violently, leaving nothing behind. 
C) The core contracts and becomes a ball of neutrons. 
D) Gravity is not able to overcome neutron degeneracy pressure. 
E) The core contracts and becomes a white dwarf.

Question 9

Which type of star spends the longest time as a protostar?

Accepted Answer

A) M star 
B) B star 
C) G star 
D) O star 
A) M star 
B) B star 
C) G star 
D) O star

Question 10

We do not know for certain whether the general trends we observe in stellar birth masses also apply to brown dwarfs. But if they do, then which of the following would be true?

Accepted Answer

A) Most of the brown dwarfs in the Milky Way Galaxy would be quite young in age. 
B) Brown dwarfs would be responsible for most of the overall luminosity of our Milky Way Galaxy. 
C) Brown dwarfs would outnumber all ordinary stars. 
D) Brown dwarfs would be extremely rare. 
A) Most of the brown dwarfs in the Milky Way Galaxy would be quite young in age. 
B) Brown dwarfs would be responsible for most of the overall luminosity of our Milky Way Galaxy. 
C) Brown dwarfs would outnumber all ordinary stars. 
D) Brown dwarfs would be extremely rare.

Question 11

You discover a binary star system in which one member is a15 solar mass main- sequence star and the other star is a 10 solar mass giant star. How do we believe that a star system such as this might have come to exist?

Accepted Answer

A) Although both stars probably formed from the same clump of gas, the more massive one must have had its birth slowed so that it became a main- sequence star millions of years later than its less massive companion. 
B) The main- sequence star probably is a pulsating variable star and therefore appears to be less massive than it really is. 
C) The two stars probably were once separate but became a binary when a close encounter allowed their mutual gravity to pull them together. 
D) Other than the very low odds of finding a system with two such massive stars, there is nothing surprising about the fact that such systems exist. 
E) The giant must once have been the more massive star but transferred some of its mass to its companion. 
A) Although both stars probably formed from the same clump of gas, the more massive one must have had its birth slowed so that it became a main- sequence star millions of years later than its less massive companion. 
B) The main- sequence star probably is a pulsating variable star and therefore appears to be less massive than it really is. 
C) The two stars probably were once separate but became a binary when a close encounter allowed their mutual gravity to pull them together. 
D) Other than the very low odds of finding a system with two such massive stars, there is nothing surprising about the fact that such systems exist. 
E) The giant must once have been the more massive star but transferred some of its mass to its companion.

Question 12

When does a protostar become a main- sequence star?

Accepted Answer

A) at the instant that the first hydrogen fusion reactions occur in the protostar's core 
B) when it becomes luminous enough to emit thermal radiation 
C) when a piece of a molecular cloud first begins to contract into a star 
D) when the rate of hydrogen fusion becomes high enough to balance the rate at which the star radiates energy into space 
A) at the instant that the first hydrogen fusion reactions occur in the protostar's core 
B) when it becomes luminous enough to emit thermal radiation 
C) when a piece of a molecular cloud first begins to contract into a star 
D) when the rate of hydrogen fusion becomes high enough to balance the rate at which the star radiates energy into space

Question 13

Which of the following properties describes a low- mass star?

Accepted Answer

A) has higher main- sequence luminosities than high mass stars 
B) ends its life as a supernova 
C) late in life, fuses carbon into oxygen 
D) has longer lifetimes than high mass stars 
A) has higher main- sequence luminosities than high mass stars 
B) ends its life as a supernova 
C) late in life, fuses carbon into oxygen 
D) has longer lifetimes than high mass stars

Question 14

Historical Supernova: You find an ancient Chinese text that speaks of a "new star" briefly visible in the constellation Sagittarius in the year 1000 B.C. You suspect that the reference is to a supernova explosion. Design an observing program to provide scientific evidence for this hypothesis. What object or objects would you look for in the sky today? What wavelengths of electromagnetic radiation would you use? How would you be sure any object you found exploded (as seen from the Earth)nearly 3000 years ago?

Accepted Answer

To provide scientific evidence for the h

Question 15

A spinning neutron star has been observed at the center of a .

Accepted Answer

A) supernova remnant 
B) protostar 
C) planetary nebula 
D) red supergiant 
A) supernova remnant 
B) protostar 
C) planetary nebula 
D) red supergiant

Question 16

After a supernova explosion, the remains of the stellar core .

Accepted Answer

A) will always be a black hole 
B) will always be a neutron star 
C) may be either a neutron star or a black hole 
D) may be either a white dwarf, neutron star, or black hole 
A) will always be a black hole 
B) will always be a neutron star 
C) may be either a neutron star or a black hole 
D) may be either a white dwarf, neutron star, or black hole

Question 17

Carbon fusion occur in high- mass stars but not in low- mass stars because .

Accepted Answer

A) the cores of low- mass stars never get hot enough for carbon fusion 
B) only high- mass stars do fusion by the CNO cycle 
C) carbon fusion can occur only in the stars known as carbon stars 
D) the cores of low- mass stars never contain significant amounts of carbon 
A) the cores of low- mass stars never get hot enough for carbon fusion 
B) only high- mass stars do fusion by the CNO cycle 
C) carbon fusion can occur only in the stars known as carbon stars 
D) the cores of low- mass stars never contain significant amounts of carbon

Question 18

This diagram represents the life track of a 1 solar mass star. Refer to the life stages labeled with roman numerals. During which stage is the star's energy supplied by primarily by gravitational contraction?

Accepted Answer

A) vi 
B) viii 
C) ii 
D) v 
E) iii 
A) vi 
B) viii 
C) ii 
D) v 
E) iii

Question 19

What types of stars end their lives with supernovae?

Accepted Answer

A) all stars that are yellow in color 
B) stars that have reached an age of 10 billion years 
C) stars that are at least several times the mass of the Sun 
D) stars that are similar in mass to the Sun 
E) all stars that are red in color 
A) all stars that are yellow in color 
B) stars that have reached an age of 10 billion years 
C) stars that are at least several times the mass of the Sun 
D) stars that are similar in mass to the Sun 
E) all stars that are red in color

Question 20

The luminosity of light emerging from the star's gaseous surface is equal to the

Accepted Answer

A) mass of the star. 
B) star's lifetime. 
C) rate of energy generated from nuclear reactions in the star's core. 
D) temperature of the star's core. 
E) star's apparent brightness. 
A) mass of the star. 
B) star's lifetime. 
C) rate of energy generated from nuclear reactions in the star's core. 
D) temperature of the star's core. 
E) star's apparent brightness.

What star is the most likely to have made the atoms of gold in your jewelry or your electronics?

Which of the following statements about brown dwarfs is not true?

Do you think it is possible that a 10- solar- mass main- sequence star could harbor an advanced civilization? Explain your reasoning.

Our Sun will end its life in a planetary nebula and become a white dwarf.

What is a planetary nebula?

Which part of the electromagnetic spectrum generally gives us our best views of stars forming in dusty clouds?

What happens when the gravity of a massive star is able to overcome neutron degeneracy pressure?

Which type of star spends the longest time as a protostar?

We do not know for certain whether the general trends we observe in stellar birth masses also apply to brown dwarfs. But if they do, then which of the following would be true?

You discover a binary star system in which one member is a15 solar mass main- sequence star and the other star is a 10 solar mass giant star. How do we believe that a star system such as this might have come to exist?

When does a protostar become a main- sequence star?

Which of the following properties describes a low- mass star?

A spinning neutron star has been observed at the center of a .

After a supernova explosion, the remains of the stellar core .

Carbon fusion occur in high- mass stars but not in low- mass stars because .

This diagram represents the life track of a 1 solar mass star. Refer to the life stages labeled with roman numerals. During which stage is the star's energy supplied by primarily by gravitational contraction?

What types of stars end their lives with supernovae?

The luminosity of light emerging from the star's gaseous surface is equal to the

A Modern View of the Universe

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Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light: the Cosmic Messenger

Formation of the Solar System

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Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Other Planetary Systems: the New Science of Distant Worlds

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Exam 13: Star Stuff

What star is the most likely to have made the atoms of gold in your jewelry or your electronics?

Which of the following statements about brown dwarfs is not true?

Do you think it is possible that a 10- solar- mass main- sequence star could harbor an advanced civilization? Explain your reasoning.

Our Sun will end its life in a planetary nebula and become a white dwarf.

What is a planetary nebula?

Which part of the electromagnetic spectrum generally gives us our best views of stars forming in dusty clouds?

What happens when the gravity of a massive star is able to overcome neutron degeneracy pressure?

Which type of star spends the longest time as a protostar?

We do not know for certain whether the general trends we observe in stellar birth masses also apply to brown dwarfs. But if they do, then which of the following would be true?

You discover a binary star system in which one member is a15 solar mass main- sequence star and the other star is a 10 solar mass giant star. How do we believe that a star system such as this might have come to exist?

When does a protostar become a main- sequence star?

Which of the following properties describes a low- mass star?

A spinning neutron star has been observed at the center of a .

After a supernova explosion, the remains of the stellar core .

Carbon fusion occur in high- mass stars but not in low- mass stars because .

This diagram represents the life track of a 1 solar mass star. Refer to the life stages labeled with roman numerals. During which stage is the star's energy supplied by primarily by gravitational contraction?

What types of stars end their lives with supernovae?

The luminosity of light emerging from the star's gaseous surface is equal to the

A Modern View of the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light: the Cosmic Messenger

Formation of the Solar System

Earth and the Terrestrial Worlds

Jovian Planet System

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Other Planetary Systems: the New Science of Distant Worlds

Our Star

Surveying the Stars

The Bizarre Stellar Graveyard

Our Galaxy

A Universe of Galaxies

The Birth of the Universe

Dark Matter, Dark Energy, and the Fate of the Universe

Life in the Universe

Filters