Question 1

Figure: Main-Sequence Stars
What is the approximate age of the star cluster in the accompanying figure?

Accepted Answer

A)  10 million years 
B)  100 million years 
C)  10 billion years 
D)  100 billion years 
E)  Cannot be determine from the given data. 
A)  10 million years 
B)  100 million years 
C)  10 billion years 
D)  100 billion years 
E)  Cannot be determine from the given data.

Question 2

Observing star clusters will give astronomers needed data for stellar evolution because all the stars in the cluster have the same ____.

Accepted Answer

A)  masses 
B)  temperatures 
C)  ages 
D)  luminosities 
E)  apparent magnitudes 
A)  masses 
B)  temperatures 
C)  ages 
D)  luminosities 
E)  apparent magnitudes

Question 3

The age of a star cluster can be approximated by finding its turnoff point in the distribution of data points that represent stars on the H-R Diagram.

Accepted Answer

A) True 
 B)False

Question 4

Match between columns
                        Premises:  _____ giants
_____ helium flash
_____ white dwarfs
_____ spectral class
_____ giants
_____ instability strip
_____ main sequence stars
_____ fusion of He into C
_____ diameter
_____ supergiants
_____ brightness
_____ ZAMS

Accepted Answer

The Answer of H and E and A and F is...

Question 5

Cepheid and RR Lyrae variable stars change their brightness by ____.

Accepted Answer

A)  atmospheric explosions of hydrogen gas 
B)  internal changes in their fusion processes 
C)  a combination of atmospheric explosions and internal changes 
D)  a combination of atmospheric explosions and physically pulsating 
E)  changing its period between pulses 
A)  atmospheric explosions of hydrogen gas 
B)  internal changes in their fusion processes 
C)  a combination of atmospheric explosions and internal changes 
D)  a combination of atmospheric explosions and physically pulsating 
E)  changing its period between pulses

Question 6

Briefly explain why there is a main sequence on the H-R Diagram.

Accepted Answer

Models of stars show that there is a mai

Question 7

The lower limit for a main sequence star is _______________ solar masses.

Accepted Answer

The answer of The lower limit for a main sequence...

Question 8

Because of the period-luminosity relation for Cepheids and RR Lyrae variable stars, astronomers are able to _____

Accepted Answer

A)  determine the relationship between the period of pulses and luminosity 
B)  measure the mass of a star 
C)  calculate a star's diameter 
D)  determine the chemical composition of a Type I Cepheid 
E)  narrow their study to eclipsing binary stars only 
A)  determine the relationship between the period of pulses and luminosity 
B)  measure the mass of a star 
C)  calculate a star's diameter 
D)  determine the chemical composition of a Type I Cepheid 
E)  narrow their study to eclipsing binary stars only

Question 9

Why is there an upper end in the main sequence of the H-R diagram?

Accepted Answer

The upper end in the main sequence of th

Question 10

The helium flash stage will always completely destroy a star and any planets nearby it

Accepted Answer

A) True 
 B)False

Question 11

The energy emitted from the surface of a main sequence star is less than the energy generated in the core.

Accepted Answer

A) True 
 B)False

Question 12

The fusion of helium into carbon will take a temperature of at least

Accepted Answer

A)  5 million degrees Kelvin 
B)  10 million degrees Kelvin 
C)  50 million degrees Kelvin 
D)  100 million degrees Kelvin 
E)  600 million degrees Kelvin 
A)  5 million degrees Kelvin 
B)  10 million degrees Kelvin 
C)  50 million degrees Kelvin 
D)  100 million degrees Kelvin 
E)  600 million degrees Kelvin

Question 13

What is the upper limit of a brown dwarf's size?

Accepted Answer

A)  no upper limit 
B)  0.50 solar masses 
C)  0.10 solar masses 
D)  0.08 solar masses 
E)  less than 0.08 solar masses 
A)  no upper limit 
B)  0.50 solar masses 
C)  0.10 solar masses 
D)  0.08 solar masses 
E)  less than 0.08 solar masses

Question 14

As a main sequence star evolves off the main sequence, the helium core is contracting while the outer envelope is _______________.

Accepted Answer

The answer of As a main sequence star evolves off...

Question 15

Observing star clusters will give astronomers needed data for stellar evolution because all the stars are the same age.

Accepted Answer

A) True 
 B)False

Question 16

The Instability Strip on the H-R Diagram is the location for what type of stars _______________.

Accepted Answer

Cepheid variables,RR

Question 17

As a one-solar-mass star evolves off the main sequence, it will probably undergo a _____.

Accepted Answer

A)  nova burnout 
B)  helium flash 
C)  hydrogen flash 
D)  helium bang 
E)  carbon flash 
A)  nova burnout 
B)  helium flash 
C)  hydrogen flash 
D)  helium bang 
E)  carbon flash

Question 18

List the two basic types of intrinsic variable stars.

Accepted Answer

1 Cepheid

Question 19

Globular clusters have approximately how many stars?

Accepted Answer

A)  100,000 - 1,000,000 
B)  10,000 - 90,000 
C)  5,000 - 10,000 
D)  1000 - 5000 
E)  less than 1000 
A)  100,000 - 1,000,000 
B)  10,000 - 90,000 
C)  5,000 - 10,000 
D)  1000 - 5000 
E)  less than 1000

Question 20

Astronomers determine the internal structure of a star by using stellar models, since they cannot "see" into the interior of a star.

Accepted Answer

A) True 
 B)False

Exam 12: Stellar Evolution

Figure: Main-Sequence Stars What is the approximate age of the star cluster in the accompanying figure?

Observing star clusters will give astronomers needed data for stellar evolution because all the stars in the cluster have the same ____.

The age of a star cluster can be approximated by finding its turnoff point in the distribution of data points that represent stars on the H-R Diagram.

Cepheid and RR Lyrae variable stars change their brightness by ____.

Briefly explain why there is a main sequence on the H-R Diagram.

The lower limit for a main sequence star is _______________ solar masses.

Because of the period-luminosity relation for Cepheids and RR Lyrae variable stars, astronomers are able to _____

Why is there an upper end in the main sequence of the H-R diagram?

The helium flash stage will always completely destroy a star and any planets nearby it

The energy emitted from the surface of a main sequence star is less than the energy generated in the core.

The fusion of helium into carbon will take a temperature of at least

What is the upper limit of a brown dwarf's size?

As a main sequence star evolves off the main sequence, the helium core is contracting while the outer envelope is _______________.

Observing star clusters will give astronomers needed data for stellar evolution because all the stars are the same age.

The Instability Strip on the H-R Diagram is the location for what type of stars _______________.

As a one-solar-mass star evolves off the main sequence, it will probably undergo a _____.

List the two basic types of intrinsic variable stars.

Globular clusters have approximately how many stars?

Astronomers determine the internal structure of a star by using stellar models, since they cannot "see" into the interior of a star.

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