Question 1

How does nucleosynthesis depend on the mass of the star?

Accepted Answer

A)  With increasing mass, heavier and heavier elements are formed throughout their interiors. 
B)  With increasing mass, heavier and heavier elements are formed in their cores. 
C)  With increasing mass, elements between helium and gold are formed in the cores. 
D)  With increasing mass, elements between helium and carbon are formed in the cores. 
E)  All stars more massive than 8 solar masses create elements from helium through uranium in their cores. 
A)  With increasing mass, heavier and heavier elements are formed throughout their interiors. 
B)  With increasing mass, heavier and heavier elements are formed in their cores. 
C)  With increasing mass, elements between helium and gold are formed in the cores. 
D)  With increasing mass, elements between helium and carbon are formed in the cores. 
E)  All stars more massive than 8 solar masses create elements from helium through uranium in their cores.

Question 2

An 8M $\odot$ star will eventually die as a Type I supernova.

Accepted Answer

A) True 
 B)False

Question 3

We can identify only a fraction of all the radio pulsars that exist in our galaxy because:

Accepted Answer

A)  gas and dust efficiently block radio photons 
B)  few swing their beam of synchrotron emission in our direction 
C)  most have evolved to become black holes, which emit no light 
D)  massive stars are very rare 
E)  neutron stars have tiny radii, and are hard to detect even with large telescopes 
A)  gas and dust efficiently block radio photons 
B)  few swing their beam of synchrotron emission in our direction 
C)  most have evolved to become black holes, which emit no light 
D)  massive stars are very rare 
E)  neutron stars have tiny radii, and are hard to detect even with large telescopes

Question 4

How does the energy in light emitted by a supernova compare to the energy emitted by the Sun during its lifetime?

Accepted Answer

A)  The supernova emits far less energy. 
B)  The supernova emits somewhat less energy. 
C)  Both emit about the same energy. 
D)  The supernova emits somewhat more energy. 
E)  The supernova emits far more energy. 
A)  The supernova emits far less energy. 
B)  The supernova emits somewhat less energy. 
C)  Both emit about the same energy. 
D)  The supernova emits somewhat more energy. 
E)  The supernova emits far more energy.

Question 5

Why do main-sequence high-mass stars lose so much mass compared to low-mass stars?

Accepted Answer

They have very strong winds be

Question 6

Do large, high-mass main-sequence stars become red giants?

Accepted Answer

No, they do not. Red giants have a degen

Question 7

With the Hubble Space Telescope, you discover a Cepheid variable star in a nearby galaxy that has a period of 30 days. If nearby Cepheids follow a period-luminosity relationship that says the luminosity of the star is L =335 L $\odot$  * (P/1 day), then what is this Cepheid's luminosity and absolute magnitude? Recall that the Sun's absolute magnitude is M = 5. If the apparent magnitude of the Cepheid is 25, what is this galaxy's distance in Mpc?

Accepted Answer

The Cepheid's luminosity is L= 335 L <su

Question 8

What is the minimum mass main-sequence star that becomes a Type II supernova?

Accepted Answer

A)  4M $\odot$ 
B)  8M $\odot$ 
C)  10M $\odot$ 
D)  12M $\odot$ 
E)  25M $\odot$ 
A)  4M $\odot$ 
B)  8M $\odot$ 
C)  10M $\odot$ 
D)  12M $\odot$ 
E)  25M $\odot$

Question 9

You observe a distant galaxy, and see that most of the blue light is coming from regions along spiral arms and in the outer regions of the galaxy. This blue light indicates that these regions contain:

Accepted Answer

A)  likely sites for planets with life 
B)  neutron stars and white dwarf stars 
C)  K-type supergiants 
D)  only old, low-mass stars 
E)  young, massive stars 
A)  likely sites for planets with life 
B)  neutron stars and white dwarf stars 
C)  K-type supergiants 
D)  only old, low-mass stars 
E)  young, massive stars

Question 10

In the CNO cycle, carbon is used a catalyst for the fusion of hydrogen to helium. This means that:

Accepted Answer

A)  three helium nuclei fuse to form carbon 
B)  carbon facilitates the reaction but is not consumed in it 
C)  carbon boosts the energy from the reaction, which is why massive stars are luminous 
D)  carbon breaks apart into three helium nuclei 
E)  the reaction produces carbon nuclei in addition to helium 
A)  three helium nuclei fuse to form carbon 
B)  carbon facilitates the reaction but is not consumed in it 
C)  carbon boosts the energy from the reaction, which is why massive stars are luminous 
D)  carbon breaks apart into three helium nuclei 
E)  the reaction produces carbon nuclei in addition to helium

Question 11

As a high-mass main-sequence star evolves off the main sequence, it follows a: __________ on the H-R diagram.

Accepted Answer

A)  nearly vertical path 
B)  path of constant radius 
C)  roughly horizontal path 
D)  path of declining luminosity 
E)  path of increasing temperature 
A)  nearly vertical path 
B)  path of constant radius 
C)  roughly horizontal path 
D)  path of declining luminosity 
E)  path of increasing temperature

Question 12

Why are star clusters helpful for testing our ideas of stellar structure and evolution?

Accepted Answer

All the stars in an individual cluster w

Question 13

If an 8M $\odot$ star loses mass at an average rate of 10 - 6 M $\odot$ /yr in a stellar wind, how many years would it take for its mass be reduced to 6M $\odot$ ? Would this amount of mass loss be possible in the star's lifetime?

Accepted Answer

If R is the mass loss rate and M is the

Question 14

Each kilogram of hydrogen that fuses into helium releases about 6*1014 Joules of energy. How many tons of hydrogen are fused each second to power a massive main-sequence star with a luminosity of 100 L $\odot$ ? Note that 1 L $\odot$  = 4 * 1026 Joule/second and 1 ton = 103 kg.

Accepted Answer

A)  2 * 106 tons 
B)  7* 107 tons 
C)  2 *109 tons 
D)  7 *1010 tons 
E)  2 * 1011 tons 
A)  2 * 106 tons 
B)  7* 107 tons 
C)  2 *109 tons 
D)  7 *1010 tons 
E)  2 * 1011 tons

Question 15

Type I and Type II supernovae are respectively caused by what types of stars?

Accepted Answer

A)  white dwarfs, Cepheid variables 
B)  white dwarfs, pulsars 
C)  massive stars, white dwarfs 
D)  massive stars, neutron stars 
E)  white dwarfs, massive stars 
A)  white dwarfs, Cepheid variables 
B)  white dwarfs, pulsars 
C)  massive stars, white dwarfs 
D)  massive stars, neutron stars 
E)  white dwarfs, massive stars

Question 16

A neutron star contains a mass of up to 3M $\odot$  in a sphere with a diameter approximately the size of:

Accepted Answer

A)  an atomic nucleus 
B)  an apple 
C)  a school bus 
D)  a city 
E)  the Earth 
A)  an atomic nucleus 
B)  an apple 
C)  a school bus 
D)  a city 
E)  the Earth

Question 17

What might be true about the oldest stars in the Milky Way?

Accepted Answer

A)  They would have lots of heavy elements, since they have been around for a long time and have undergone a lot of nucleosynthesis in their cores. 
B)  They would be seen as supergiants. 
C)  They would have few heavy elements, since there was not much chance for earlier generations of stars to explode as supernovae before these stars were formed. 
D)  They would be massive, since they were among the first stars formed. 
E)  They would likely be seen as pulsars. 
A)  They would have lots of heavy elements, since they have been around for a long time and have undergone a lot of nucleosynthesis in their cores. 
B)  They would be seen as supergiants. 
C)  They would have few heavy elements, since there was not much chance for earlier generations of stars to explode as supernovae before these stars were formed. 
D)  They would be massive, since they were among the first stars formed. 
E)  They would likely be seen as pulsars.

Question 18

Which of the following is NOT a common characteristic of a neutron star?

Accepted Answer

A)  extremely high density 
B)  enormous magnetic field 
C)  very short rotation period 
D)  large radius 
E)  source of pulsars 
A)  extremely high density 
B)  enormous magnetic field 
C)  very short rotation period 
D)  large radius 
E)  source of pulsars

Question 19

Pulsating variable stars are more commonly known as pulsars.

Accepted Answer

A) True 
 B)False

Question 20

When the core of a massive star collapses, a neutron star forms because:

Accepted Answer

A)  all the charged particles are ejected in the resulting explosion 
B)  protons and electrons combine to make neutrons 
C)  iron nuclei disintegrate into neutrons 
D)  neutrinos escaping from the core carry away most of the electromagnetic charge 
E)  the collapse releases a large number of protons, which soon decay into neutrons 
A)  all the charged particles are ejected in the resulting explosion 
B)  protons and electrons combine to make neutrons 
C)  iron nuclei disintegrate into neutrons 
D)  neutrinos escaping from the core carry away most of the electromagnetic charge 
E)  the collapse releases a large number of protons, which soon decay into neutrons

Exam 17: Evolution of High-Mass Stars

How does nucleosynthesis depend on the mass of the star?

An 8M ⊙\odot⊙ star will eventually die as a Type I supernova.

We can identify only a fraction of all the radio pulsars that exist in our galaxy because:

How does the energy in light emitted by a supernova compare to the energy emitted by the Sun during its lifetime?

Why do main-sequence high-mass stars lose so much mass compared to low-mass stars?

Do large, high-mass main-sequence stars become red giants?

What is the minimum mass main-sequence star that becomes a Type II supernova?

You observe a distant galaxy, and see that most of the blue light is coming from regions along spiral arms and in the outer regions of the galaxy. This blue light indicates that these regions contain:

In the CNO cycle, carbon is used a catalyst for the fusion of hydrogen to helium. This means that:

As a high-mass main-sequence star evolves off the main sequence, it follows a: __________ on the H-R diagram.

Why are star clusters helpful for testing our ideas of stellar structure and evolution?

If an 8M ⊙\odot⊙ star loses mass at an average rate of 10 - 6 M ⊙\odot⊙ /yr in a stellar wind, how many years would it take for its mass be reduced to 6M ⊙\odot⊙ ? Would this amount of mass loss be possible in the star's lifetime?

Each kilogram of hydrogen that fuses into helium releases about 6*1014 Joules of energy. How many tons of hydrogen are fused each second to power a massive main-sequence star with a luminosity of 100 L ⊙\odot⊙ ? Note that 1 L ⊙\odot⊙ = 4 * 1026 Joule/second and 1 ton = 103 kg.

Type I and Type II supernovae are respectively caused by what types of stars?

A neutron star contains a mass of up to 3M ⊙\odot⊙ in a sphere with a diameter approximately the size of:

What might be true about the oldest stars in the Milky Way?

Which of the following is NOT a common characteristic of a neutron star?

Pulsating variable stars are more commonly known as pulsars.

When the core of a massive star collapses, a neutron star forms because:

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Relativity and Black Holes

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

Large-Scale Structure in the Universe

Life

Filters

An 8M _$\odot$ star will eventually die as a Type I supernova.

If an 8M _$\odot$ star loses mass at an average rate of 10 ^- ⁶ M _$\odot$ /yr in a stellar wind, how many years would it take for its mass be reduced to 6M _$\odot$ ? Would this amount of mass loss be possible in the star's lifetime?

Each kilogram of hydrogen that fuses into helium releases about 610¹⁴ Joules of energy. How many tons of hydrogen are fused each second to power a massive main-sequence star with a luminosity of 100 L _$\odot$ ? Note that 1 L _$\odot$ = 4 10²⁶ Joule/second and 1 ton = 10³ kg.

A neutron star contains a mass of up to 3M _$\odot$ in a sphere with a diameter approximately the size of: