Question 1

Which objects are NOT very young stars or prestellar objects?

Accepted Answer

A)  red giants 
B)  infrared-emitting stars in gas and dust clouds 
C)  protostars 
D)  T Tauri stars 
A)  red giants 
B)  infrared-emitting stars in gas and dust clouds 
C)  protostars 
D)  T Tauri stars

Question 2

What is a protostar called in the stage after it has finished accreting mass?

Accepted Answer

A)  a white dwarf 
B)  a red giant (or supergiant) 
C)  a pre-main-sequence star 
D)  a main-sequence star 
A)  a white dwarf 
B)  a red giant (or supergiant) 
C)  a pre-main-sequence star 
D)  a main-sequence star

Question 3

How long did the Sun spend in the protostar phase of its life?

Accepted Answer

A)  4.6 billion years 
B)  400,000 years 
C)  50,000 years 
D)  20 million years 
A)  4.6 billion years 
B)  400,000 years 
C)  50,000 years 
D)  20 million years

Question 4

The energy emitted by a star increases as the fourth power of its surface temperature and a red giant star has a lower temperature than the Sun.Why then is the luminosity of a red giant about a thousand times greater than that of the Sun?

Accepted Answer

A)  A red giant is bigger and therefore has a much larger surface area. 
B)  The energy transfer from a red giant's interior is much more efficient than the transfer is in the Sun. 
C)  More of a red giant's total output of energy is in the visible range than is the energy of the Sun, and hence the red giant appears brighter. 
D)  A red giant's nuclear furnace produces much more energy than does that of the Sun. 
A)  A red giant is bigger and therefore has a much larger surface area. 
B)  The energy transfer from a red giant's interior is much more efficient than the transfer is in the Sun. 
C)  More of a red giant's total output of energy is in the visible range than is the energy of the Sun, and hence the red giant appears brighter. 
D)  A red giant's nuclear furnace produces much more energy than does that of the Sun.

Question 5

What is the "safety valve" that prevents normal (nondegenerate)stars from self-destructing?

Accepted Answer

A)  If the pressure rises, the volume occupied by the matter decreases, reducing the nuclear reaction rate. 
B)  If a part of a star where thermonuclear reactions are occurring is suddenly heated, it expands and cools. 
C)  If thermonuclear reactions proceed too quickly, the star runs out of fuel before anything drastic happens. 
D)  If the temperature rises, the thermonuclear reaction rate increases to match it. 
A)  If the pressure rises, the volume occupied by the matter decreases, reducing the nuclear reaction rate. 
B)  If a part of a star where thermonuclear reactions are occurring is suddenly heated, it expands and cools. 
C)  If thermonuclear reactions proceed too quickly, the star runs out of fuel before anything drastic happens. 
D)  If the temperature rises, the thermonuclear reaction rate increases to match it.

Question 6

What is believed to be the MAXIMUM mass a star can have?

Accepted Answer

A)  about 50 solar masses 
B)  about 1000 solar masses 
C)  about 150 solar masses 
D)  about 500 solar masses 
A)  about 50 solar masses 
B)  about 1000 solar masses 
C)  about 150 solar masses 
D)  about 500 solar masses

Question 7

After it leaves the main sequence,a star of more than 1 solar mass moves generally to the right on the H-R diagram because the star's:

Accepted Answer

A)  surface temperature is increasing while its radius is decreasing. 
B)  surface temperature is decreasing while its radius is increasing. 
C)  core is expanding while its outer layers are contracting. 
D)  core is expanding, causing its outer layers to expand as well. 
A)  surface temperature is increasing while its radius is decreasing. 
B)  surface temperature is decreasing while its radius is increasing. 
C)  core is expanding while its outer layers are contracting. 
D)  core is expanding, causing its outer layers to expand as well.

Question 8

The light from a distant cloud of gas and dust looks distinctly red to the naked eye.When a spectrum is taken,it is found that many wavelengths that would normally be expected to be in the middle of the spectrum have been shifted into the long wavelength end of the spectrum.Thus,the red color in this situation is due to:

Accepted Answer

A)  interstellar reddening. 
B)  the Balmer spectrum of hydrogen. 
C)  the Doppler effect. 
D)  interstellar reddening, the Balmer spectrum of hydrogen, or the Doppler effect. 
A)  interstellar reddening. 
B)  the Balmer spectrum of hydrogen. 
C)  the Doppler effect. 
D)  interstellar reddening, the Balmer spectrum of hydrogen, or the Doppler effect.

Question 9

In a group of stars with a range of masses,stars with different mass:

Accepted Answer

A)  leave the main sequence of the Hertzsprung-Russell diagram at different times after their birth. 
B)  have about the same age, as massive stars burn their fuel more rapidly than low-mass stars. 
C)  all go through the supernova phase of evolution at varying times after their births. 
D)  all pass, at some stage in their evolution, through one particular point on the Hertzsprung-Russell diagram, occupied at present by the Sun. 
A)  leave the main sequence of the Hertzsprung-Russell diagram at different times after their birth. 
B)  have about the same age, as massive stars burn their fuel more rapidly than low-mass stars. 
C)  all go through the supernova phase of evolution at varying times after their births. 
D)  all pass, at some stage in their evolution, through one particular point on the Hertzsprung-Russell diagram, occupied at present by the Sun.

Question 10

The age of a cluster can be determined by:

Accepted Answer

A)  carrying out a number count of the stars in the cluster. 
B)  measuring the cluster's speed of motion relative to the Sun. 
C)  determining the turnoff point on the main sequence of the cluster's Hertzsprung-Russell diagram. 
D)  observing the cluster's position in the sky with respect to the Sun. 
A)  carrying out a number count of the stars in the cluster. 
B)  measuring the cluster's speed of motion relative to the Sun. 
C)  determining the turnoff point on the main sequence of the cluster's Hertzsprung-Russell diagram. 
D)  observing the cluster's position in the sky with respect to the Sun.

Question 11

If you were to look at 1 kilogram of material taken from the surface of the Sun and 1 kilogram taken from the center,which statement would be TRUE of the two kilograms?

Accepted Answer

A)  Both kilograms have the same amount of hydrogen and are in fact mostly hydrogen. 
B)  The kilogram from the surface contains more hydrogen than the one from the center. 
C)  Neither kilogram contains any hydrogen. 
D)  The kilogram from the surface contains less hydrogen than the one from the center. 
A)  Both kilograms have the same amount of hydrogen and are in fact mostly hydrogen. 
B)  The kilogram from the surface contains more hydrogen than the one from the center. 
C)  Neither kilogram contains any hydrogen. 
D)  The kilogram from the surface contains less hydrogen than the one from the center.

Question 12

The T Tauri phase of a protostar is characterized by:

Accepted Answer

A)  the ejection of a planetary nebula. 
B)  strong spectral absorption lines of metals. 
C)  strong spectral emission lines. 
D)  the helium flash. 
A)  the ejection of a planetary nebula. 
B)  strong spectral absorption lines of metals. 
C)  strong spectral emission lines. 
D)  the helium flash.

Question 13

A star of which solar mass would NOT be expected to experience a helium flash?

Accepted Answer

A)  0.2 
B)  0.8 
C)  1.2 
D)  1.8 
A)  0.2 
B)  0.8 
C)  1.2 
D)  1.8

Question 14

All stars on the main sequence:

Accepted Answer

A)  generate energy by hydrogen fusion in their centers. 
B)  have approximately the same age, to within a few million years. 
C)  are changing slowly in size, by gravitational contraction. 
D)  are at a late stage of evolution, after the red giant stage. 
A)  generate energy by hydrogen fusion in their centers. 
B)  have approximately the same age, to within a few million years. 
C)  are changing slowly in size, by gravitational contraction. 
D)  are at a late stage of evolution, after the red giant stage.

Question 15

T Tauri stars are at what stage of stellar evolution?

Accepted Answer

A)  main sequence, or "middle age" 
B)  horizontal-branch phase 
C)  early phase-after protostar but before main sequence 
D)  post-main sequence, before helium shell flash 
A)  main sequence, or "middle age" 
B)  horizontal-branch phase 
C)  early phase-after protostar but before main sequence 
D)  post-main sequence, before helium shell flash

Question 16

What is the turnoff point for a star cluster?

Accepted Answer

A)  a point in the Hertzsprung-Russell diagram occupied by stars undergoing (or about to undergo) the helium flash 
B)  a point in the Hertzsprung-Russell diagram occupied by the highest-mass main-sequence stars in the cluster 
C)  a point in the Hertzsprung-Russell diagram occupied by the lowest-mass main-sequence stars in the cluster 
D)  a point in the Hertzsprung-Russell diagram occupied by the highest-mass stars that have not yet reached the main sequence 
A)  a point in the Hertzsprung-Russell diagram occupied by stars undergoing (or about to undergo) the helium flash 
B)  a point in the Hertzsprung-Russell diagram occupied by the highest-mass main-sequence stars in the cluster 
C)  a point in the Hertzsprung-Russell diagram occupied by the lowest-mass main-sequence stars in the cluster 
D)  a point in the Hertzsprung-Russell diagram occupied by the highest-mass stars that have not yet reached the main sequence

Question 17

The distinctive color of a reflection nebula is:

Accepted Answer

A)  the light of all colors predominantly in the red part of the spectrum, emitted by cool stars and reflected by crystals of water ice surrounding the stars. 
B)  several specific colors, resulting from fluorescence of atoms excited by ultraviolet radiation emitted by hot stars. 
C)  blue, caused by the scattering of light from dust grains. 
D)  red, resulting from the emission of light from hydrogen gas. 
A)  the light of all colors predominantly in the red part of the spectrum, emitted by cool stars and reflected by crystals of water ice surrounding the stars. 
B)  several specific colors, resulting from fluorescence of atoms excited by ultraviolet radiation emitted by hot stars. 
C)  blue, caused by the scattering of light from dust grains. 
D)  red, resulting from the emission of light from hydrogen gas.

Question 18

Interstellar extinction is the:

Accepted Answer

A)  assimilation of interstellar matter by stars after gravitational attraction and capture. 
B)  reduction of the apparent brightness of stars by scattering and absorption of their light by intervening interstellar clouds. 
C)  wipe-out of species on Earth by intense radiation from a nearby supernova. 
D)  deaths of high-mass stars in the space between other long-lived stars. 
A)  assimilation of interstellar matter by stars after gravitational attraction and capture. 
B)  reduction of the apparent brightness of stars by scattering and absorption of their light by intervening interstellar clouds. 
C)  wipe-out of species on Earth by intense radiation from a nearby supernova. 
D)  deaths of high-mass stars in the space between other long-lived stars.

Question 19

The temperature at which thermonuclear reactions begin to convert helium into carbon (helium burning)is:

Accepted Answer

A)  15 million K. 
B)  100 million K. 
C)  1 billion K. 
D)  1 million K. 
A)  15 million K. 
B)  100 million K. 
C)  1 billion K. 
D)  1 million K.

Question 20

Which property is NOT a characteristic of T Tauri stars?

Accepted Answer

A)  variations in brightness 
B)  ejection of mass into space 
C)  nuclear reactions in the core 
D)  emission lines in the spectrum 
A)  variations in brightness 
B)  ejection of mass into space 
C)  nuclear reactions in the core 
D)  emission lines in the spectrum

Which objects are NOT very young stars or prestellar objects?

What is a protostar called in the stage after it has finished accreting mass?

How long did the Sun spend in the protostar phase of its life?

The energy emitted by a star increases as the fourth power of its surface temperature and a red giant star has a lower temperature than the Sun.Why then is the luminosity of a red giant about a thousand times greater than that of the Sun?

What is the "safety valve" that prevents normal (nondegenerate)stars from self-destructing?

What is believed to be the MAXIMUM mass a star can have?

After it leaves the main sequence,a star of more than 1 solar mass moves generally to the right on the H-R diagram because the star's:

In a group of stars with a range of masses,stars with different mass:

The age of a cluster can be determined by:

If you were to look at 1 kilogram of material taken from the surface of the Sun and 1 kilogram taken from the center,which statement would be TRUE of the two kilograms?

The T Tauri phase of a protostar is characterized by:

A star of which solar mass would NOT be expected to experience a helium flash?

All stars on the main sequence:

T Tauri stars are at what stage of stellar evolution?

What is the turnoff point for a star cluster?

The distinctive color of a reflection nebula is:

Interstellar extinction is the:

The temperature at which thermonuclear reactions begin to convert helium into carbon (helium burning)is:

Which property is NOT a characteristic of T Tauri stars?

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Deaths and Remnants of Stars

The Galaxies

Cosmology

Astrobiology

Filters

Exam 11: The Lives of the Stars From Birth Through Middle Age

Which objects are NOT very young stars or prestellar objects?

What is a protostar called in the stage after it has finished accreting mass?

How long did the Sun spend in the protostar phase of its life?

The energy emitted by a star increases as the fourth power of its surface temperature and a red giant star has a lower temperature than the Sun.Why then is the luminosity of a red giant about a thousand times greater than that of the Sun?

What is the "safety valve" that prevents normal (nondegenerate)stars from self-destructing?

What is believed to be the MAXIMUM mass a star can have?

After it leaves the main sequence,a star of more than 1 solar mass moves generally to the right on the H-R diagram because the star's:

In a group of stars with a range of masses,stars with different mass:

The age of a cluster can be determined by:

If you were to look at 1 kilogram of material taken from the surface of the Sun and 1 kilogram taken from the center,which statement would be TRUE of the two kilograms?

The T Tauri phase of a protostar is characterized by:

A star of which solar mass would NOT be expected to experience a helium flash?

All stars on the main sequence:

T Tauri stars are at what stage of stellar evolution?

What is the turnoff point for a star cluster?

The distinctive color of a reflection nebula is:

Interstellar extinction is the:

The temperature at which thermonuclear reactions begin to convert helium into carbon (helium burning)is:

Which property is NOT a characteristic of T Tauri stars?

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Deaths and Remnants of Stars

The Galaxies

Cosmology

Astrobiology

Filters