Question 1

Once silicon burning begins to fuse iron in the core of a high-mass main-sequence star,it only has a few __________ left to live.

Accepted Answer

The answer of Once silicon burning begins to fuse iron...

Question 2

In the figure below,when elements from section A undergo fusion,energy is _______.Because of this fact,it would be ________ to find a high-mass main sequence star with a high concentration of elements from section B.

Accepted Answer

The answer of In the figure below,when elements from section...

Question 3

What would happen if mass were continually added to a 2 M_$\bigodot$neutron star?

Accepted Answer

As more mass is added to the neutron star, its gravitational force becomes stronger, causing it to collapse further and further in on itself. Eventually, a critical point is reached where the gravitational force is so strong that it overwhelms all other forces, and the neutron star undergoes a catastrophic collapse to become a black hole. There would be no increase in the star's radius, and it would not erupt as a nova. Therefore, only choice B is the best answer.

Question 4

Once carbon begins burning in the core of a high-mass star,the outer layers begin to fall inward,driving up the fusion rates and speeding up the star's evolution primarily because:

Accepted Answer

As the outer layers of the star fall inward, they become denser and the temperature increases, causing the fusion rates to speed up. However, a significant amount of the energy produced by fusion is carried away from the core by escaping neutrinos, which have very low interaction rates with matter and can easily leave the star, effectively carrying away energy and further fueling the fusion process. This phenomenon, known as the neutrino loss catastrophe, is a major factor in the evolution of high-mass stars.

Question 5

Essentially all the elements heavier than iron in our galaxy were formed:

Accepted Answer

Elements heavier than iron cannot be formed by nuclear fusion in stars, as it requires energy rather than releases it. They can only be formed in supernova explosions, where there is enough energy to create these elements through neutron capture and rapid neutron synthesis.

Question 6

Neutron stars have masses that range from:

Accepted Answer

Neutron stars typically have masses between about 1.4 and 3 solar masses (M_☉).

Question 7

During the main-sequence evolution of a massive star,increasingly heavier elements are fused in the core,giving the core support for:

Accepted Answer

The answer of During the main-sequence evolution of a massive...

Question 8

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

Accepted Answer

The minimum mass main-sequence star that becomes a Type II supernova is about 8 solar masses (M☉). This is because stars with masses higher than 8M☉ have a core that is hot enough to synthesize heavier elements, like iron. When the core runs out of fuel, it collapses under its own weight and releases a burst of energy in the form of a supernova. Stars with masses below 8M☉ do not have a core that is hot enough to synthesize heavier elements, so they will not experience a Type II supernova.

Question 9

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

Accepted Answer

The answer of As a high-mass main-sequence star evolves off...

Question 10

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

Accepted Answer

A neutron star is incredibly dense, with a mass up to 3 times that of the Sun compressed into a sphere with a diameter of about 20 kilometers, roughly the size of a city.

Question 11

The main difference between Cepheid variable stars and RR Lyrae stars is:

Accepted Answer

The answer of The main difference between Cepheid variable stars...

Question 12

The collapse of the core of a high-mass star at the end of its life lasts approximately:

Accepted Answer

The collapse of the core of a high-mass star, known as a Type II supernova, lasts only about one second. This rapid collapse leads to the formation of a neutron star or black hole.

Question 13

Why does the luminosity of a high-mass star remain nearly constant as the star burns heavy elements in its core,even though it is producing millions of times more energy per second than it did on the main sequence?

Accepted Answer

The answer of Why does the luminosity of a high-mass...

Question 14

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

Accepted Answer

All three characteristics—extremely high density, enormous magnetic field, and very short rotation period—are common characteristics of a neutron star.

Question 15

The Type II supernova that created the Crab Nebula (image below)was seen by Chinese and Arab astronomers in the year A.D.1054 Because the star is 6,500 light-years away from us,we know the star exploded in the year:

Accepted Answer

The answer of The Type II supernova that created the...

Question 16

An iron core cannot support a massive main-sequence star because:

Accepted Answer

Iron cannot fuse with other nuclei to produce energy, which means there is no energy generation to counteract the gravitational force pulling the star inward. This causes the star to collapse, leading to a supernova explosion.

Question 17

A Cepheid star varies in luminosity because:

Accepted Answer

Cepheid stars vary in luminosity because the outer envelope of the star pulsates, causing changes in its radius and temperature.

Question 18

If a 25 M_$\bigodot$ main-sequence star loses mass at a rate of 10^-6 M_$\bigodot$/yr then how much mass will it lose in its 3-million-year lifetime?

Accepted Answer

To find the total mass lost in a 3-million-year lifetime, we need to multiply the mass loss rate with the time period:

Mass loss = mass loss rate x time period
Mass loss = 10S1U1P1-6S1S1P0 MF1S1S1W1S1U1B1S1U1B0F1F1F10/yr x 3 x 10S1U1P6S1S1P0F10 yr
Mass loss = 3 MF1S1S1W1S1U1B1S1U1B0F1F1F10

Therefore, the star will lose a total of 3 MF1S1S1W1S1U1B1S1U1B0F1F1F10 in its 3-million-year lifetime, which makes the correct answer choice (A).

Question 19

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

Accepted Answer

Pulsars emit beams of synchrotron emission that sweep around their magnetic poles. Only a small fraction of all pulsars will have their beams directed toward Earth, making them detectable as pulsating radio sources. The radio photons are not blocked by gas and dust, and there is no evidence that most pulsars have evolved into black holes. Mass of stars, both small and large, have no bearing on the detection of pulsars.

Question 20

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

Accepted Answer

The answer of When the core of a massive star...

Quiz 13: Evolution of High-Mass Stars

Once silicon burning begins to fuse iron in the core of a high-mass main-sequence star,it only has a few __________ left to live.

In the figure below,when elements from section A undergo fusion,energy is _.Because of this fact,it would be __ to find a high-mass main sequence star with a high concentration of elements from section B.

What would happen if mass were continually added to a 2 M_$\bigodot$neutron star?

Once carbon begins burning in the core of a high-mass star,the outer layers begin to fall inward,driving up the fusion rates and speeding up the star's evolution primarily because:

Essentially all the elements heavier than iron in our galaxy were formed:

Neutron stars have masses that range from:

During the main-sequence evolution of a massive star,increasingly heavier elements are fused in the core,giving the core support for:

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

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

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

The main difference between Cepheid variable stars and RR Lyrae stars is:

The collapse of the core of a high-mass star at the end of its life lasts approximately:

Why does the luminosity of a high-mass star remain nearly constant as the star burns heavy elements in its core,even though it is producing millions of times more energy per second than it did on the main sequence?

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

The Type II supernova that created the Crab Nebula (image below) was seen by Chinese and Arab astronomers in the year A.D.1054 Because the star is 6,500 light-years away from us,we know the star exploded in the year:

An iron core cannot support a massive main-sequence star because:

A Cepheid star varies in luminosity because:

If a 25 M_$\bigodot$ main-sequence star loses mass at a rate of 10^-6 M_$\bigodot$/yr then how much mass will it lose in its 3-million-year lifetime?

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

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

Quiz 13: Evolution of High-Mass Stars

Once silicon burning begins to fuse iron in the core of a high-mass main-sequence star,it only has a few __________ left to live.

In the figure below,when elements from section A undergo fusion,energy is _______.Because of this fact,it would be ________ to find a high-mass main sequence star with a high concentration of elements from section B.

What would happen if mass were continually added to a 2 M ⨀\bigodot⨀ neutron star?

Once carbon begins burning in the core of a high-mass star,the outer layers begin to fall inward,driving up the fusion rates and speeding up the star's evolution primarily because:

Essentially all the elements heavier than iron in our galaxy were formed:

Neutron stars have masses that range from:

During the main-sequence evolution of a massive star,increasingly heavier elements are fused in the core,giving the core support for:

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

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

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

The main difference between Cepheid variable stars and RR Lyrae stars is:

The collapse of the core of a high-mass star at the end of its life lasts approximately:

Why does the luminosity of a high-mass star remain nearly constant as the star burns heavy elements in its core,even though it is producing millions of times more energy per second than it did on the main sequence?

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

The Type II supernova that created the Crab Nebula (image below) was seen by Chinese and Arab astronomers in the year A.D.1054 Because the star is 6,500 light-years away from us,we know the star exploded in the year:

An iron core cannot support a massive main-sequence star because:

A Cepheid star varies in luminosity because:

If a 25 M ⨀\bigodot⨀ main-sequence star loses mass at a rate of 10-6 M ⨀\bigodot⨀ /yr then how much mass will it lose in its 3-million-year lifetime?

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

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

In the figure below,when elements from section A undergo fusion,energy is _.Because of this fact,it would be __ to find a high-mass main sequence star with a high concentration of elements from section B.

What would happen if mass were continually added to a 2 M_$\bigodot$neutron star?

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

If a 25 M_$\bigodot$ main-sequence star loses mass at a rate of 10^-6 M_$\bigodot$/yr then how much mass will it lose in its 3-million-year lifetime?