Question 1

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 2

Variables of a certain type are called Cepheid variables because the first one discovered was in the _____________ Cepheus.

Accepted Answer

The answer of Variables of a certain type are called...

Question 3

Explain how the age of a star cluster provides evidence of stellar evolution.

Accepted Answer

All the stars in a cluster are understoo

Question 4

Why do Cepheids pulsate?

Accepted Answer

Studies using stellar models show that v

Question 5

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 6

Stellar models can easily be accomplished by using a simple hand calculator.

Accepted Answer

A) True 
 B)False

Question 7

Why are massive stars more luminous than low mass stars? That is, why is there a mass-luminosity relation?

Accepted Answer

The mass-luminosity relation exists beca

Question 8

Cepheid variables can be used to determine distances because their _____________ can be determined from their _____________.

Accepted Answer

absolute m

Question 9

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 10

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 11

Why is there a lower end in the main sequence of the H-R diagram?

Accepted Answer

The lower end in the main sequence show

Question 12

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 13

Where are the Cepheid and RR Lyrae variable stars located on the H-R Diagram?

Accepted Answer

A)  just above and to the right of B type stars 
B)  just above and to the right of O type stars 
C)  in the variable strip 
D)  in the instability strip 
E)  outside the H-R Diagram as missing items 
A)  just above and to the right of B type stars 
B)  just above and to the right of O type stars 
C)  in the variable strip 
D)  in the instability strip 
E)  outside the H-R Diagram as missing items

Question 14

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

Accepted Answer

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

Question 15

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

Accepted Answer

Cepheid variables,RR

Question 16

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

Accepted Answer

The Answer of E and K and G and I is...

Question 17

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

Accepted Answer

A) True 
 B)False

Question 18

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 19

Why is the Cepheid's period related to their luminosity?

Accepted Answer

The longer-period Cepheids are about 40,

Question 20

Brown dwarfs are ____.

Accepted Answer

A)  stars with a very thick dust sphere around them, so they appear "brown" 
B)  low mass M type stars with hundreds of planets 
C)  an anomaly because they are extremely small but have relatively high temperature 
D)  protostars that could not ignite the fusion of hydrogen at their core 
E)  has a surface temperature of 2500 K by fusing hydrogen 
A)  stars with a very thick dust sphere around them, so they appear "brown" 
B)  low mass M type stars with hundreds of planets 
C)  an anomaly because they are extremely small but have relatively high temperature 
D)  protostars that could not ignite the fusion of hydrogen at their core 
E)  has a surface temperature of 2500 K by fusing hydrogen

Exam 12: Stellar Evolution

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

Variables of a certain type are called Cepheid variables because the first one discovered was in the _____________ Cepheus.

Explain how the age of a star cluster provides evidence of stellar evolution.

Why do Cepheids pulsate?

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

Stellar models can easily be accomplished by using a simple hand calculator.

Why are massive stars more luminous than low mass stars? That is, why is there a mass-luminosity relation?

Cepheid variables can be used to determine distances because their _____________ can be determined from their _____________.

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

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

Why is there a lower end in the main sequence of the H-R diagram?

Globular clusters have approximately how many stars?

Where are the Cepheid and RR Lyrae variable stars located on the H-R Diagram?

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

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

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

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

Why is the Cepheid's period related to their luminosity?

Brown dwarfs are ____.

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