Question 1

Relate hydrostatic equilibrium to the star's mass, composition, and evolution off the mainsequence.

Accepted Answer

Hydrostatic equilibrium means that the inward force of gravity, a product of the star'smass, is exactly balanced by the outward radiation pressure of its thermonuclear reactions; aslong as the hydrogen supply is abundant, this balance can be maintained, and the star is stable onthe main sequence. Once the core helium content grows, and the hydrogen burning shellexpands, this extra radiation temporarily overwhelms gravity, and the star begins swelling intoits giant stage of evolution.

Question 2

What inevitably forces a star like the Sun to evolve away from being a main sequence star?

Accepted Answer

A) The core begins fusing iron. 
B) The star uses up all its supply of hydrogen. 
C) The carbon detonation explodes it as a type I supernova. 
D) Helium builds up in the core, while the hydrogen burning shell expands. 
E) The core loses all its neutrinos, so all fusion ceases. 
A) The core begins fusing iron. 
B) The star uses up all its supply of hydrogen. 
C) The carbon detonation explodes it as a type I supernova. 
D) Helium builds up in the core, while the hydrogen burning shell expands. 
E) The core loses all its neutrinos, so all fusion ceases. D

Question 3

What is a planetary nebula?

Accepted Answer

A) the bipolar jets ejected by a T Tauri variable 
B) a planet surrounded by a glowing shell of gas 
C) the disk of gas and dust surrounding a young star that will soon form a solar system 
D) the ejected envelope, often bipolar, of a red giant surrounding a stellar core remnant 
E) a type of young, medium mass star 
A) the bipolar jets ejected by a T Tauri variable 
B) a planet surrounded by a glowing shell of gas 
C) the disk of gas and dust surrounding a young star that will soon form a solar system 
D) the ejected envelope, often bipolar, of a red giant surrounding a stellar core remnant 
E) a type of young, medium mass star D

Question 4

The Sun will get brighter in the next 4 to 5 billion years.

Accepted Answer

A) True 
 B)False

Question 5

Refer to the figure above. What is the name of the path between the points labeled 13 and14?

Accepted Answer

A) planetary nebula 
B) red giant branch 
C) horizontal branch 
D) asymptotic giant branch 
E) white dwarf 
A) planetary nebula 
B) red giant branch 
C) horizontal branch 
D) asymptotic giant branch 
E) white dwarf

Question 6

A star cluster of age 100 million years contains no type O stars.

Accepted Answer

A) True 
 B)False

Question 7

While more massive than most of its neighbors, the Sun is still technically a low mass star.

Accepted Answer

A) True 
 B)False

Question 8

Eventually, all low mass stars will become white, then black, dwarfs.

Accepted Answer

A) True 
 B)False

Question 9

Which of these will the Sun probably become in the very distant future?

Accepted Answer

A) hypernova 
B) supernova 
C) pulsar 
D) planetary nebula 
E) nova 
A) hypernova 
B) supernova 
C) pulsar 
D) planetary nebula 
E) nova

Question 10

Discuss the source of energy for a star like the Sun when it is on the Main Sequence. Includethe role of nuclear, electrical, and gravitational forces, temperature, and chemical composition.How long can this star burn its fuel and what marks the end of this stage of its life?

Accepted Answer

The Sun produces energy via the proton-p

Question 11

What spectral type of star that is still around formed most recently?

Accepted Answer

A) O 
B) A 
C) F 
D) K 
E) M 
A) O 
B) A 
C) F 
D) K 
E) M

Question 12

A(n)________ stage is a relatively gentle mass-loss event which allows a star to peacefullyreadjust its structure into a white dwarf configuration.

Accepted Answer

The answer of A(n)________ stage is a relatively gentle mass-loss...

Question 13

What element are most white dwarfs primarily made of? Why?

Accepted Answer

They consist largely of carbon, for it i

Question 14

Which is used observationally to determine the age of a star cluster?

Accepted Answer

A) the total number of main sequence stars 
B) the ratio of giants to supergiants 
C) the luminosity of the main sequence turn-off point 
D) the number of white dwarfs 
E) the amount of dust that lies around the cluster 
A) the total number of main sequence stars 
B) the ratio of giants to supergiants 
C) the luminosity of the main sequence turn-off point 
D) the number of white dwarfs 
E) the amount of dust that lies around the cluster

Question 15

How have Hubble images revised our view of the structure of planetary nebulae, and even thepotential for the Sun to become one?

Accepted Answer

Instead of just spherical shells, we kno

Question 16

During various stages of evolution, low mass stars (like the Sun)differ significantly fromhigh mass stars. How do they differ in terms of observational properties while Main Sequencestars?

Accepted Answer

High mass stars are blue or wh

Question 17

Evolution of a star off the main sequence is caused by the loss of mass from hydrogen fusionby the star while a main sequence star.

Accepted Answer

A) True 
 B)False

Question 18

What temperature is needed to fuse helium into carbon?

Accepted Answer

A) 5,800 K 
B) 100,000 K 
C) 15 million K 
D) 100 million K 
E) one billion K 
A) 5,800 K 
B) 100,000 K 
C) 15 million K 
D) 100 million K 
E) one billion K

Question 19

The matter in white dwarfs is about a million times denser than matter around you, since youhave packed the mass of the Sun into the volume of our Earth.

Accepted Answer

A) True 
 B)False

Question 20

In globular clusters, the brightest stars will be:

Accepted Answer

A) massive blue main sequence stars. 
B) red supergiants. 
C) T Tauri stars. 
D) blue stragglers. 
E) planetary nebulae. 
A) massive blue main sequence stars. 
B) red supergiants. 
C) T Tauri stars. 
D) blue stragglers. 
E) planetary nebulae.

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

Relate hydrostatic equilibrium to the star's mass, composition, and evolution off the mainsequence.

What inevitably forces a star like the Sun to evolve away from being a main sequence star?

What is a planetary nebula?

The Sun will get brighter in the next 4 to 5 billion years.

Refer to the figure above. What is the name of the path between the points labeled 13 and14?

A star cluster of age 100 million years contains no type O stars.

While more massive than most of its neighbors, the Sun is still technically a low mass star.

Eventually, all low mass stars will become white, then black, dwarfs.

Which of these will the Sun probably become in the very distant future?

Discuss the source of energy for a star like the Sun when it is on the Main Sequence. Includethe role of nuclear, electrical, and gravitational forces, temperature, and chemical composition.How long can this star burn its fuel and what marks the end of this stage of its life?

What spectral type of star that is still around formed most recently?

A(n)________ stage is a relatively gentle mass-loss event which allows a star to peacefullyreadjust its structure into a white dwarf configuration.

What element are most white dwarfs primarily made of? Why?

Which is used observationally to determine the age of a star cluster?

How have Hubble images revised our view of the structure of planetary nebulae, and even thepotential for the Sun to become one?

During various stages of evolution, low mass stars (like the Sun)differ significantly fromhigh mass stars. How do they differ in terms of observational properties while Main Sequencestars?

Evolution of a star off the main sequence is caused by the loss of mass from hydrogen fusionby the star while a main sequence star.

What temperature is needed to fuse helium into carbon?

The matter in white dwarfs is about a million times denser than matter around you, since youhave packed the mass of the Sun into the volume of our Earth.

In globular clusters, the brightest stars will be:

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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