Question 1

Describe the physical mechanism that causes pulsations in Cepheid variables.

Accepted Answer

During the contraction phase of the puls

Question 2

Name three processes that speed the collapse of the core of a dying high-mass star.

Accepted Answer

(1)Photodisintegration uses up the therm

Question 3

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 4

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

A) seconds 
B) days 
C) months 
D) years 
E) million years 
A) seconds 
B) days 
C) months 
D) years 
E) million years

Question 5

A neutron star in a mass-transfer binary system is called:

Accepted Answer

A) a quasar 
B) a double star 
C) an X-ray binary 
D) a Cepheid variable 
E) a white dwarf star 
A) a quasar 
B) a double star 
C) an X-ray binary 
D) a Cepheid variable 
E) a white dwarf star

Question 6

Type I and Type II supernovae can be distinguished by what combination of observations?

Accepted Answer

A) light curves and the detection of energetic cosmic rays 
B) light curves and the detection of neutrons 
C) light curves and the detection of radio pulses 
D) spectra and light curves 
E) spectra and X-ray emission 
A) light curves and the detection of energetic cosmic rays 
B) light curves and the detection of neutrons 
C) light curves and the detection of radio pulses 
D) spectra and light curves 
E) spectra and X-ray emission

Question 7

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 8

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

Accepted Answer

A) 3M⨀ 
B) 5M⨀ 
C) 8M⨀ 
D) 10M⨀ 
E) 12M⨀ 
A) 3M⨀ 
B) 5M⨀ 
C) 8M⨀ 
D) 10M⨀ 
E) 12M⨀

Question 9

We can determine the age of a star cluster because stars of different masses go through their lives at different rates.

Accepted Answer

A) True 
 B)False

Question 10

Of all the main-sequence stars ever formed with a mass equal to 25 percent of the Sun's mass,how many are still on the main sequence today?

Accepted Answer

A) none 
B) 1 percent 
C) 10 percent 
D) 50 percent 
E) 100 percent 
A) none 
B) 1 percent 
C) 10 percent 
D) 50 percent 
E) 100 percent

Question 11

Massive stars explode when they:

Accepted Answer

A) accrete mass from their binary star companion 
B) generate uranium in their cores 
C) merge with another massive star 
D) run out of nuclear fuel in their core,and the cores collapse 
E) lose a lot of mass in a stellar wind 
A) accrete mass from their binary star companion 
B) generate uranium in their cores 
C) merge with another massive star 
D) run out of nuclear fuel in their core,and the cores collapse 
E) lose a lot of mass in a stellar wind

Question 12

The acceleration from gravity on the surface of a neutron star can be how large compared to the value on the surface of the Earth? For reference,the typical mass of a neutron star is 2 M⨀ and its radius is approximately 10 km.

Accepted Answer

A) equal in size 
B) 10 times as large 
C) 104 times as large 
D) 107 times as large 
E) 1011 times as large 
A) equal in size 
B) 10 times as large 
C) 104 times as large 
D) 107 times as large 
E) 1011 times as large

Question 13

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 14

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 15

List the following H-R diagrams from oldest to youngest.

Accepted Answer

A) 2,1,3,4 
B) 1,4,3,2 
C) 4,3,1,2 
D) 1,2,4,3 
E) 3,1,4,2 
A) 2,1,3,4 
B) 1,4,3,2 
C) 4,3,1,2 
D) 1,2,4,3 
E) 3,1,4,2

Question 16

Why does the CNO cycle happen only in high-mass stars?

Accepted Answer

The CNO cycle requires protons to collid

Question 17

What is one way that massive stars differ from low-mass stars?

Accepted Answer

A) They are found at cooler temperatures on the main sequence. 
B) They fuse carbon through silicon without leaving the main sequence. 
C) Convection is important in their cores,which determines when the stars leave the main sequence. 
D) They turn into red giants explosively. 
E) Most of their fusion energy is emitted as neutrinos and not visible light. 
A) They are found at cooler temperatures on the main sequence. 
B) They fuse carbon through silicon without leaving the main sequence. 
C) Convection is important in their cores,which determines when the stars leave the main sequence. 
D) They turn into red giants explosively. 
E) Most of their fusion energy is emitted as neutrinos and not visible light.

Question 18

Why do massive stars explode once they generate an iron core?

Accepted Answer

Burning of light elements,up to iron in

Question 19

Each stage of nuclear burning in 25 M⨀ star is __________ in duration than in a star of 15 M⨀.

Accepted Answer

A) much shorter 
B) a little shorter 
C) equally long 
D) a little longer 
E) much longer 
A) much shorter 
B) a little shorter 
C) equally long 
D) a little longer 
E) much longer

Question 20

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.

Exam 17: Evolution of High-Mass Stars

Describe the physical mechanism that causes pulsations in Cepheid variables.

Name three processes that speed the collapse of the core of a dying high-mass star.

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

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.

A neutron star in a mass-transfer binary system is called:

Type I and Type II supernovae can be distinguished by what combination of observations?

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

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

We can determine the age of a star cluster because stars of different masses go through their lives at different rates.

Of all the main-sequence stars ever formed with a mass equal to 25 percent of the Sun's mass,how many are still on the main sequence today?

Massive stars explode when they:

The acceleration from gravity on the surface of a neutron star can be how large compared to the value on the surface of the Earth? For reference,the typical mass of a neutron star is 2 M⨀ and its radius is approximately 10 km.

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?

List the following H-R diagrams from oldest to youngest.

Why does the CNO cycle happen only in high-mass stars?

What is one way that massive stars differ from low-mass stars?

Why do massive stars explode once they generate an iron core?

Each stage of nuclear burning in 25 M⨀ star is __________ in duration than in a star of 15 M⨀.

How does nucleosynthesis depend on the mass of the star?

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 Adornments Moons 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

If a 25M_⨀ main-sequence star loses mass at a rate of 10⁻⁶ M_⨀/yr,then how much mass will it lose in its lifetime of 3 million years?

The acceleration from gravity on the surface of a neutron star can be how large compared to the value on the surface of the Earth? For reference,the typical mass of a neutron star is 2 M_⨀ and its radius is approximately 10 km.

Each stage of nuclear burning in 25 M_⨀ star is __________ in duration than in a star of 15 M_⨀.