Question 1

Compared to a cluster containing type O and B stars, a cluster with only type F and coolerstars will be:

Accepted Answer

A) younger. 
B) older. 
C) further away. 
D) more obscured by dust. 
E) less obscured by dust. 
A) younger. 
B) older. 
C) further away. 
D) more obscured by dust. 
E) less obscured by dust.

Question 2

Refer to the figure above. At what numbered point on the graph above does the helium flashoccur?

Accepted Answer

A) 7 
B) 8 
C) 9 
D) 10 
E) 11 
A) 7 
B) 8 
C) 9 
D) 10 
E) 11

Question 3

The shell ejection in making a planetary nebula is spherical and symmetrical in all cases.

Accepted Answer

A) True 
 B)False

Question 4

In a fairly young star cluster, if the most massive stars are swelling up into giants, the leastmassive stars are:

Accepted Answer

A) also evolving off the main sequence as well. 
B) continuing to shine as stable main sequence stars. 
C) blowing off shells as planetary nebula instead. 
D) collapsing directly to white dwarfs. 
E) still evolving toward their ZAMS positions. 
A) also evolving off the main sequence as well. 
B) continuing to shine as stable main sequence stars. 
C) blowing off shells as planetary nebula instead. 
D) collapsing directly to white dwarfs. 
E) still evolving toward their ZAMS positions.

Question 5

In an H-R Diagram, the path showing changes in a star's luminosity and surface temperatureas a function of time is called its ________.

Accepted Answer

The answer of In an H-R Diagram, the path showing...

Question 6

What is a typical age for a globular cluster?

Accepted Answer

A) 10 million years 
B) 200 million years 
C) one billion years 
D) 4.8 billion years 
E) 12 billion years 
A) 10 million years 
B) 200 million years 
C) one billion years 
D) 4.8 billion years 
E) 12 billion years

Question 7

How has the chemical composition of the core of the Sun changed in the past 4.5 billionyears? Are earthlings (if any)likely to freeze in another 4-5 billion years? Explain.

Accepted Answer

The core of the Sun had an initial compo

Question 8

Just as a low-mass main sequence star runs out of fuel in its core, it actually becomesbrighter. How is this possible?

Accepted Answer

A) Helium fusion gives more energy than hydrogen fusion does, based on masses. 
B) Its outer envelope is stripped away and we see the brilliant core. 
C) The core contracts, raising the temperature and increasing the size of the region of hydrogenshell-burning. 
D) It explodes. 
E) It immediately starts to fuse helium. 
A) Helium fusion gives more energy than hydrogen fusion does, based on masses. 
B) Its outer envelope is stripped away and we see the brilliant core. 
C) The core contracts, raising the temperature and increasing the size of the region of hydrogenshell-burning. 
D) It explodes. 
E) It immediately starts to fuse helium.

Question 9

Some globular clusters have three main sequence tracks. This indicates:

Accepted Answer

A) three different stellar compositions. 
B) three episodes of star formation, separated by billions of years. 
C) stars evolve through three different mechanisms. 
D) the stars were observed from three different telescopes. 
A) three different stellar compositions. 
B) three episodes of star formation, separated by billions of years. 
C) stars evolve through three different mechanisms. 
D) the stars were observed from three different telescopes.

Question 10

In general, as stars go through the last stage of post-main sequence evolution, they will losemass in the process of settling down into their final state. Explain the mass-loss process and thefinal state of the star for a low mass star.

Accepted Answer

For a low mass star, the hydrogen fuel i

Question 11

The Main Sequence is the first stellar stage in which energy produced by ________ balancesthe energy lost by radiation from the surface of the star.

Accepted Answer

fusion (of hydrogen

Question 12

Describe what the internal structure of the Sun looks like, indicating what physicalphenomena are occurring there. In what respects (internal structure, energy generation, etc.)doesthe internal structure of a high mass Main Sequence star differ from that of the Sun?

Accepted Answer

Nuclear fusion via the proton-proton cyc

Question 13

What is the typical age for a globular cluster associated with our Milky Way?

Accepted Answer

A) a few million years 
B) 200 million years 
C) a billion years 
D) 10-12 billion years 
E) 45 billion years 
A) a few million years 
B) 200 million years 
C) a billion years 
D) 10-12 billion years 
E) 45 billion years

Question 14

The brightest stars in aging globular clusters will be:

Accepted Answer

A) core stars of planetary nebulae. 
B) massive blue main sequence stars like Spica. 
C) blue stragglers. 
D) red supergiants like Betelgeuse and Antares. 
E) blue supergiants like Rigel and Deneb. 
A) core stars of planetary nebulae. 
B) massive blue main sequence stars like Spica. 
C) blue stragglers. 
D) red supergiants like Betelgeuse and Antares. 
E) blue supergiants like Rigel and Deneb.

Question 15

A solar mass star will evolve off the main sequence when:

Accepted Answer

A) it completely runs out of hydrogen. 
B) it expels a planetary nebula to cool off and release radiation. 
C) it explodes as a violent nova. 
D) it builds up a core of inert helium. 
E) it loses all its neutrinos, so fusion must cease. 
A) it completely runs out of hydrogen. 
B) it expels a planetary nebula to cool off and release radiation. 
C) it explodes as a violent nova. 
D) it builds up a core of inert helium. 
E) it loses all its neutrinos, so fusion must cease.

Question 16

There is no helium flash for a high mass star; for them, it is just one more step toward theheaviest element formation.

Accepted Answer

A) True 
 B)False

Question 17

During a helium flash, what happens to the star? Does it get brighter? Why or why not?

Accepted Answer

The energy released in a helium flash ex

Question 18

Compared to our Sun, a typical white dwarf has:

Accepted Answer

A) about the same mass and density. 
B) about the same mass and a million times higher density. 
C) a larger mass and a 100 times lower density. 
D) a smaller mass and half the density. 
E) a smaller mass and twice the density. 
A) about the same mass and density. 
B) about the same mass and a million times higher density. 
C) a larger mass and a 100 times lower density. 
D) a smaller mass and half the density. 
E) a smaller mass and twice the density.

Question 19

When a low-mass star runs out of hydrogen in its core, it gets brighter. Why?

Accepted Answer

Without radiation pressure to

Question 20

What is a helium flash?

Accepted Answer

A helium flash is a runaway condition ca

Exam 20: Stellar Evolution: The Life and Death of a Star

Compared to a cluster containing type O and B stars, a cluster with only type F and coolerstars will be:

Refer to the figure above. At what numbered point on the graph above does the helium flashoccur?

The shell ejection in making a planetary nebula is spherical and symmetrical in all cases.

In a fairly young star cluster, if the most massive stars are swelling up into giants, the leastmassive stars are:

In an H-R Diagram, the path showing changes in a star's luminosity and surface temperatureas a function of time is called its ________.

What is a typical age for a globular cluster?

How has the chemical composition of the core of the Sun changed in the past 4.5 billionyears? Are earthlings (if any)likely to freeze in another 4-5 billion years? Explain.

Just as a low-mass main sequence star runs out of fuel in its core, it actually becomesbrighter. How is this possible?

Some globular clusters have three main sequence tracks. This indicates:

In general, as stars go through the last stage of post-main sequence evolution, they will losemass in the process of settling down into their final state. Explain the mass-loss process and thefinal state of the star for a low mass star.

The Main Sequence is the first stellar stage in which energy produced by ________ balancesthe energy lost by radiation from the surface of the star.

Describe what the internal structure of the Sun looks like, indicating what physicalphenomena are occurring there. In what respects (internal structure, energy generation, etc.)doesthe internal structure of a high mass Main Sequence star differ from that of the Sun?

What is the typical age for a globular cluster associated with our Milky Way?

The brightest stars in aging globular clusters will be:

A solar mass star will evolve off the main sequence when:

There is no helium flash for a high mass star; for them, it is just one more step toward theheaviest element formation.

During a helium flash, what happens to the star? Does it get brighter? Why or why not?

Compared to our Sun, a typical white dwarf has:

When a low-mass star runs out of hydrogen in its core, it gets brighter. Why?

What is a helium flash?

Charting the Heavens: The Foundations of Astronomy

The Copernican Revolution: The Birth of Modern Science

Radiation: Information From the Cosmos

Spectroscopy: the Inner Workings of Atoms

Telescopes: The Tools of Astronomy

The Solar System: Comparative Planetology and Formation Models

Earth: Our Home in Space

The Moon and Mercury: Scorched and Battered Worlds

Venus: Earths Sister Planet

Mars: a Near Miss for Life

Jupiter: Giant of the Solar System

Saturn: Spectacular Rings and Mysterious Moons

Uranus and Neptune: The Outer Worlds of the Solar System

Solar System Debris: Keys to Our Origin

Exoplanets: Planetary Systems Beyond Our Own

The Sun: Our Parent Star

The Stars: Giants, Dwarfs, and the Main Sequence

The Interstellar Medium: Gas and Dust Among the Stars

Star Formation: a Traumatic Birth

Stellar Explosions: Novae, Supernovae, and the Formation of the Elements

Neutron Stars and Black Holes: Strange States of Matter

The Milky Way Galaxy: a Spiral in Space

Galaxies: Building Blocks of the Universe

Galaxies and Dark Matter: The Large-Scale Structure of the Cosmos

Cosmology: The Big Bang and the Fate of the Universe

The Early Universe: Toward the Beginning of Time

Life in the Universe: Are We Alone

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