Question 1

What is "degenerate" in the degenerate core of a white dwarf?

Accepted Answer

Only the electrons a

Question 2

Degenerate refers to a state of matter at

Accepted Answer

A)  high temperature. 
B)  high density. 
C)  high luminosity. 
D)  high mass. 
A)  high temperature. 
B)  high density. 
C)  high luminosity. 
D)  high mass.

Question 3

How many times longer does a   main-sequence star live compared to a   main-sequence star?

Accepted Answer

Main-sequence liftet

Question 4

When a G2 star leaves the main sequence,

Accepted Answer

A)  its luminosity and surface temperature both stay the same. 
B)  its luminosity and surface temperature both decrease. 
C)  its luminosity increases and its surface temperature decreases. 
D)  its luminosity and surface temperature both increase. 
A)  its luminosity and surface temperature both stay the same. 
B)  its luminosity and surface temperature both decrease. 
C)  its luminosity increases and its surface temperature decreases. 
D)  its luminosity and surface temperature both increase.

Question 5

Asymptotic giant branch (AGB)stars have high-mass loss rates because

Accepted Answer

A)  they are rotating quickly. 
B)  they have weak magnetic fields. 
C)  they have strong winds. 
D)  they have low surface gravity. 
A)  they are rotating quickly. 
B)  they have weak magnetic fields. 
C)  they have strong winds. 
D)  they have low surface gravity.

Question 6

The main-sequence lifetime of a star is given by the equation

Accepted Answer

A)    . 
B)    . 
C)    . 
D)    . 
A)    . 
B)    . 
C)    . 
D)    .

Question 7

A low-mass main-sequence star's climb up the red giant branch is halted by

Accepted Answer

A)  the end of hydrogen shell burning. 
B)  the beginning of helium fusion in the core. 
C)  electron-degeneracy pressure in the core. 
D)  instabilities in the star's expanding outer layers. 
A)  the end of hydrogen shell burning. 
B)  the beginning of helium fusion in the core. 
C)  electron-degeneracy pressure in the core. 
D)  instabilities in the star's expanding outer layers.

Question 8

Explain the significance of Roche lobes in a binary system.

Accepted Answer

The Roche lobe is an imaginary line of e

Question 9

Helium burns in the core of a horizontal branch star via __________ and produces __________.

Accepted Answer

A)  the triple-alpha reaction;carbon 
B)  the proton-proton chain;lithium 
C)  the triple-alpha reaction;oxygen 
D)  the proton-proton chain;iron 
A)  the triple-alpha reaction;carbon 
B)  the proton-proton chain;lithium 
C)  the triple-alpha reaction;oxygen 
D)  the proton-proton chain;iron

Question 10

As a red giant star evolves,hydrogen shell burning proceeds increasingly faster due to

Accepted Answer

A)  rotational energy from the star's rapid rotation. 
B)  heat released from the core's contraction. 
C)  pressure from the contracting envelope. 
D)  This is a trick question.Hydrogen actually burns increasingly slower with time. 
A)  rotational energy from the star's rapid rotation. 
B)  heat released from the core's contraction. 
C)  pressure from the contracting envelope. 
D)  This is a trick question.Hydrogen actually burns increasingly slower with time.

Question 11

A low-mass red giant star's energy comes from

Accepted Answer

A)  hydrogen burning to helium in its core. 
B)  helium burning to carbon in its core. 
C)  hydrogen burning to helium in a shell surrounding its core. 
D)  helium burning to carbon in a shell surrounding its core. 
A)  hydrogen burning to helium in its core. 
B)  helium burning to carbon in its core. 
C)  hydrogen burning to helium in a shell surrounding its core. 
D)  helium burning to carbon in a shell surrounding its core.

Question 12

What types of chemical elements can low-mass stars contribute to the enrichment of the interstellar medium and how are they produced?

Accepted Answer

Low-mass stars can enrich the interstell

Question 13

When helium fusion begins in the core of a red giant star,the situation quickly gets out of control because electron-degeneracy pressure does not respond to changes in

Accepted Answer

A)  luminosity. 
B)  density. 
C)  gravity. 
D)  temperature. 
A)  luminosity. 
B)  density. 
C)  gravity. 
D)  temperature.

Question 14

What stops a red giant from cooling to continuously lower temperatures,and why?

Accepted Answer

The H^- ion: It acts as a thermostat by re

Question 15

How can the core of a star be degenerate with respect to the electrons but nondegenerate with respect to the nuclei?

Accepted Answer

(1)Quantum mechanics says electrons take

Question 16

What is the shortest phase of evolution for a one solar mass star that we can visibly see?

Accepted Answer

The planetary nebula phase is

Question 17

What is a planetary nebula?

Accepted Answer

A)  A planet surrounded by a glowing shell of gas 
B)  The disk of gas and dust surrounding a young star that will soon form a star system 
C)  The ejected envelope of a giant star surrounding the remains of a star 
D)  A type of young,medium-mass star 
A)  A planet surrounded by a glowing shell of gas 
B)  The disk of gas and dust surrounding a young star that will soon form a star system 
C)  The ejected envelope of a giant star surrounding the remains of a star 
D)  A type of young,medium-mass star

Question 18

The Sun will likely stop being a main-sequence star in

Accepted Answer

A)  5,000 years. 
B)  5 million years. 
C)  500 million years. 
D)  5 billion years. 
A)  5,000 years. 
B)  5 million years. 
C)  500 million years. 
D)  5 billion years.

Question 19

A   star will evolve through the same phases as a   star.

Accepted Answer

A) True 
 B)False

Question 20

If the Milky Way formed stars at approximately a constant rate over the last 14 billion years,what fraction of the M stars that ever formed in it can still be found as main-sequence stars today? Note that M stars have a mass of approximately   .

Accepted Answer

A)  10 percent 
B)  33 percent 
C)  50 percent 
D)  100 percent 
A)  10 percent 
B)  33 percent 
C)  50 percent 
D)  100 percent

Exam 16: Stars in the Slow Lanelow-Mass Stellar Evolution

What is "degenerate" in the degenerate core of a white dwarf?

Degenerate refers to a state of matter at

How many times longer does a main-sequence star live compared to a main-sequence star?

When a G2 star leaves the main sequence,

Asymptotic giant branch (AGB)stars have high-mass loss rates because

The main-sequence lifetime of a star is given by the equation

A low-mass main-sequence star's climb up the red giant branch is halted by

Explain the significance of Roche lobes in a binary system.

Helium burns in the core of a horizontal branch star via __________ and produces __________.

As a red giant star evolves,hydrogen shell burning proceeds increasingly faster due to

A low-mass red giant star's energy comes from

What types of chemical elements can low-mass stars contribute to the enrichment of the interstellar medium and how are they produced?

When helium fusion begins in the core of a red giant star,the situation quickly gets out of control because electron-degeneracy pressure does not respond to changes in

What stops a red giant from cooling to continuously lower temperatures,and why?

How can the core of a star be degenerate with respect to the electrons but nondegenerate with respect to the nuclei?

What is the shortest phase of evolution for a one solar mass star that we can visibly see?

What is a planetary nebula?

The Sun will likely stop being a main-sequence star in

A star will evolve through the same phases as a star.

If the Milky Way formed stars at approximately a constant rate over the last 14 billion years,what fraction of the M stars that ever formed in it can still be found as main-sequence stars today? Note that M stars have a mass of approximately .

Why Learn Astronomy

Patterns in the Skymotions of Earth

Gravity and Orbitsa Celestial Ballet

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 Liquidthe Giant Planets

Gravity Is More Than Keplers Laws

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

A Run-Of-The-Mill G-Type Starour Sun

Star Formation and the Interstellar Medium

Live Fast,die Younghigh-Mass Stellar Evolution

Our Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

The Origin of Structure

Life

Filters

Helium burns in the core of a horizontal branch star via and produces .