Question 1

A star in the instability strip pulsates because

Accepted Answer

A)  the energy produced by the core is not constant. 
B)  the energy produced by the hydrogen burning shell is not constant. 
C)  the core of the star is composed of helium and degenerate electrons. 
D)  the surface temperature of the star is increasing. 
E)  density and opacity of the helium ionization zone changes with time. 
A)  the energy produced by the core is not constant. 
B)  the energy produced by the hydrogen burning shell is not constant. 
C)  the core of the star is composed of helium and degenerate electrons. 
D)  the surface temperature of the star is increasing. 
E)  density and opacity of the helium ionization zone changes with time. E

Question 2

The figure shows an HST image of the red giant star,Betelgeuse.In the red giant stage,hydrogen is being fused to helium ...

Accepted Answer

A)  on the surface of the star 
B)  in the center of the star's helium core 
C)  on the outside of the star's helium core 
D)  Neither helium nor hydrogen is being fused in the red giant stage. 
A)  on the surface of the star 
B)  in the center of the star's helium core 
C)  on the outside of the star's helium core 
D)  Neither helium nor hydrogen is being fused in the red giant stage. C

Question 3

The ____________________ is the thermonuclear fusion of helium to form carbon.

Accepted Answer

triple alpha process

Question 4

What is the approximate age of the star cluster in the diagram below?

Accepted Answer

A)  2 million years 
B)  2 billion years 
C)  10 billion years 
D)  100 billion years 
E)  The age of the cluster cannot be estimated from an HR diagram of the cluster. 
A)  2 million years 
B)  2 billion years 
C)  10 billion years 
D)  100 billion years 
E)  The age of the cluster cannot be estimated from an HR diagram of the cluster.

Question 5

Stars with masses greater than 1.1 solar masses use the ____________________ to convert hydrogen into helium and produce energy.

Accepted Answer

The answer of Stars with masses greater than 1.1 solar...

Question 6

Variables of a certain type are called Cepheid variable because

Accepted Answer

A)  the first one discovered was in the constellation of Cepheus. 
B)  they were discovered by Anna Marie Cepheid and her brother Raul. 
C)  they all lie in the Cepheus star cluster. 
D)  they can be used to determine the distance to Cepheid star clusters. 
E)  they can be used to determine the distance to all of the stars in the Cepheid galaxy. 
A)  the first one discovered was in the constellation of Cepheus. 
B)  they were discovered by Anna Marie Cepheid and her brother Raul. 
C)  they all lie in the Cepheus star cluster. 
D)  they can be used to determine the distance to Cepheid star clusters. 
E)  they can be used to determine the distance to all of the stars in the Cepheid galaxy.

Question 7

The changing period of a Cepheid variable tells us that the

Accepted Answer

A)  star's luminosity is increasing. 
B)  surface temperature of the star is increasing. 
C)  hydrogen burning core has quit burning its nuclear fuel. 
D)  star is evolving. 
E)  star is about to undergo helium flash. 
A)  star's luminosity is increasing. 
B)  surface temperature of the star is increasing. 
C)  hydrogen burning core has quit burning its nuclear fuel. 
D)  star is evolving. 
E)  star is about to undergo helium flash.

Question 8

Of the stars in the instability strip,the more massive stars have longer periods and lower luminosities.

Accepted Answer

A) True 
 B)False

Question 9

When the Cepheid variable RU Camelopardalis stopped pulsating,astronomers speculated that it was

Accepted Answer

A)  exhausting its helium. 
B)  exhausting its hydrogen. 
C)  turning off its triple alpha process. 
D)  evolving out of the instability strip. 
E)  becoming a red supergiant. 
A)  exhausting its helium. 
B)  exhausting its hydrogen. 
C)  turning off its triple alpha process. 
D)  evolving out of the instability strip. 
E)  becoming a red supergiant.

Question 10

A young star cluster will have ____ than an older star cluster.

Accepted Answer

A)  a redder turn-off point 
B)  a bluer turn-off point 
C)  fewer stars 
D)  fewer luminous stars 
E)  more low mass stars 
A)  a redder turn-off point 
B)  a bluer turn-off point 
C)  fewer stars 
D)  fewer luminous stars 
E)  more low mass stars

Question 11

Cepheid variables can be used to determine distances because their absolute magnitude can be determined from their period.

Accepted Answer

A) True 
 B)False

Question 12

Young star clusters have bluer turn-off points than old clusters.

Accepted Answer

A) True 
 B)False

Question 13

Which of the following nuclear fuels does a 0.2 solar mass star use over the course of its entire evolution?

Accepted Answer

A)  hydrogen 
B)  hydrogen and helium 
C)  hydrogen,helium,and carbon 
D)  hydrogen,helium,carbon,and neon 
E)  hydrogen,helium,carbon,neon,and oxygen 
A)  hydrogen 
B)  hydrogen and helium 
C)  hydrogen,helium,and carbon 
D)  hydrogen,helium,carbon,and neon 
E)  hydrogen,helium,carbon,neon,and oxygen

Question 14

Helium flash occurs

Accepted Answer

A)  because helium is very explosive and cannot be controlled when the nuclear reactions occur. 
B)  because degenerate electrons in the core do not allow the core to expand as it heats up. 
C)  in Cepheid variables. 
D)  in stars with masses less than 0.4. 
E)  none of the above 
A)  because helium is very explosive and cannot be controlled when the nuclear reactions occur. 
B)  because degenerate electrons in the core do not allow the core to expand as it heats up. 
C)  in Cepheid variables. 
D)  in stars with masses less than 0.4. 
E)  none of the above

Question 15

Energy can flow outward from the cores of different kinds of stars by

Accepted Answer

A)  conduction 
B)  convection 
C)  radiation 
D)  all of the above 
A)  conduction 
B)  convection 
C)  radiation 
D)  all of the above

Question 16

There is a mass-luminosity relation because

Accepted Answer

A)  hydrogen fusion produces helium. 
B)  stars expand when they become giants. 
C)  stars support their weight by making energy. 
D)  the helium flash occurs in degenerate matter. 
E)  all stars on the main sequence have about the same radius. 
A)  hydrogen fusion produces helium. 
B)  stars expand when they become giants. 
C)  stars support their weight by making energy. 
D)  the helium flash occurs in degenerate matter. 
E)  all stars on the main sequence have about the same radius.

Question 17

A star will experience a helium flash if

Accepted Answer

A)  it is more massive than about 6 solar masses. 
B)  its core contains oxygen and helium. 
C)  its mass on the main sequence was less than 0.1 solar masses. 
D)  it is a supergiant. 
E)  its core is degenerate when helium ignites. 
A)  it is more massive than about 6 solar masses. 
B)  its core contains oxygen and helium. 
C)  its mass on the main sequence was less than 0.1 solar masses. 
D)  it is a supergiant. 
E)  its core is degenerate when helium ignites.

Question 18

The pressure of a gas depends on the temperature and density of the gas.

Accepted Answer

A) True 
 B)False

Question 19

Some massive stars only live a few million years.

Accepted Answer

A) True 
 B)False

Question 20

Giant and supergiant stars are rare because

Accepted Answer

A)  they do not form as often as main sequence stars. 
B)  the giant and supergiant stage is unstable. 
C)  the giant and supergiant stage is very short. 
D)  helium is very rare. 
E)  helium flash destroys many of the stars before they can become giants and supergiants. 
A)  they do not form as often as main sequence stars. 
B)  the giant and supergiant stage is unstable. 
C)  the giant and supergiant stage is very short. 
D)  helium is very rare. 
E)  helium flash destroys many of the stars before they can become giants and supergiants.

Exam 12: Stellar Evolution

A star in the instability strip pulsates because

The figure shows an HST image of the red giant star,Betelgeuse.In the red giant stage,hydrogen is being fused to helium ...

The ____________________ is the thermonuclear fusion of helium to form carbon.

What is the approximate age of the star cluster in the diagram below?

Stars with masses greater than 1.1 solar masses use the ____________________ to convert hydrogen into helium and produce energy.

Variables of a certain type are called Cepheid variable because

The changing period of a Cepheid variable tells us that the

Of the stars in the instability strip,the more massive stars have longer periods and lower luminosities.

When the Cepheid variable RU Camelopardalis stopped pulsating,astronomers speculated that it was

A young star cluster will have ____ than an older star cluster.

Cepheid variables can be used to determine distances because their absolute magnitude can be determined from their period.

Young star clusters have bluer turn-off points than old clusters.

Which of the following nuclear fuels does a 0.2 solar mass star use over the course of its entire evolution?

Helium flash occurs

Energy can flow outward from the cores of different kinds of stars by

There is a mass-luminosity relation because

A star will experience a helium flash if

The pressure of a gas depends on the temperature and density of the gas.

Some massive stars only live a few million years.

Giant and supergiant stars are rare because

Here and Now

A Users Guide to the Sky

Cycles of the Moon

The Origin of Modern Astronomy

Gravity

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Interstellar Medium

The Formation and Structure of Stars

The Deaths of Stars

Neutron Stars and Black Holes

The Milky Way Galaxy

Galaxies

Active Galaxies and Supermassive Black Holes

Modern Cosmology

The Origin of the Solar System

Earth: the Standard of Comparative Planetology

The Moon and Mercury: Comparing Airless Worlds

Venus and Mars

Jupiter and Saturn

Uranus,neptune,and the Kuiper Belt

Meteorites,asteroids,and Comets

Astrobiology: Life on Other Worlds

Filters