Question 1

Which range of electromagnetic radiation is MOST useful for observing newborn protostars in their gas and dust nebulae?

Accepted Answer

A)  infrared 
B)  visible 
C)  highly penetrating X-ray 
D)  radio 
A)  infrared 
B)  visible 
C)  highly penetrating X-ray 
D)  radio

Question 2

What is unusual about main-sequence stars that are about 75 percent the mass of the Sun?

Accepted Answer

A)  These stars fuse deuterium and lithium instead of hydrogen. 
B)  These stars are too small to develop any nuclear reactions. 
C)  None of these stars has yet evolved off the main sequence. 
D)  These stars develop fission reactions rather than fusion reactions in their cores. 
A)  These stars fuse deuterium and lithium instead of hydrogen. 
B)  These stars are too small to develop any nuclear reactions. 
C)  None of these stars has yet evolved off the main sequence. 
D)  These stars develop fission reactions rather than fusion reactions in their cores.

Question 3

Electron degeneracy, which is a result of the Pauli exclusion principle, is important in

Accepted Answer

A)  a Cepheid variable that is burning helium in its core. 
B)  the core of a star during core hydrogen burning. 
C)  a protostar evolving toward the main sequence. 
D)  the core of a star just before the start of core helium burning. 
A)  a Cepheid variable that is burning helium in its core. 
B)  the core of a star during core hydrogen burning. 
C)  a protostar evolving toward the main sequence. 
D)  the core of a star just before the start of core helium burning.

Question 4

What is a typical size for a giant molecular cloud?

Accepted Answer

A)  100 ly across 
B)  1000 ly across 
C)  anything up to about 1 ly across 
D)  5 ly across 
A)  100 ly across 
B)  1000 ly across 
C)  anything up to about 1 ly across 
D)  5 ly across

Question 5

At what stage in its life does a star pass through the protostar phase?

Accepted Answer

A)  while it is converting hydrogen into helium in its core 
B)  when it is expanding in size as a red giant or supergiant 
C)  after nuclear reactions end in its core but before the red giant phase 
D)  after dense core collapse but before nuclear reactions begin in its core 
A)  while it is converting hydrogen into helium in its core 
B)  when it is expanding in size as a red giant or supergiant 
C)  after nuclear reactions end in its core but before the red giant phase 
D)  after dense core collapse but before nuclear reactions begin in its core

Question 6

At what temperature do nuclear reactions begin in the core of a pre-main-sequence star?

Accepted Answer

A)  100 million K 
B)  1 million K 
C)  10 million K 
D)  100,000 K 
A)  100 million K 
B)  1 million K 
C)  10 million K 
D)  100,000 K

Question 7

Evidence of massive amounts of hydrogen gas surrounding some young, hot stars comes from

Accepted Answer

A)  observation of the reddening of the spectra of these stars because of absorption of blue light by hydrogen. 
B)  observation of emission characteristic of red Balmer light from nebulosity around them. 
C)  theoretical calculations that correctly describe stellar formation by the gravitational contraction of hydrogen gas. 
D)  observation of the blue glow from scattered light in their reflection nebulae. 
A)  observation of the reddening of the spectra of these stars because of absorption of blue light by hydrogen. 
B)  observation of emission characteristic of red Balmer light from nebulosity around them. 
C)  theoretical calculations that correctly describe stellar formation by the gravitational contraction of hydrogen gas. 
D)  observation of the blue glow from scattered light in their reflection nebulae.

Question 8

Why do many H II regions glow with a prominent red color?

Accepted Answer

A)  Ionized hydrogen, like neutral hydrogen, has the Hα line as one of its electron transitions. 
B)  Ionized hydrogen does not emit a red line, but it has a yellow line and a magenta line, and the combination of these produces the sensation of red. 
C)  Ionized hydrogen cannot be detected directly, so CO is used as a tracer, and CO produces a red line. 
D)  Neutral hydrogen atoms are formed temporarily in the plasma of an H II region, and they emit the red Hα line. 
A)  Ionized hydrogen, like neutral hydrogen, has the Hα line as one of its electron transitions. 
B)  Ionized hydrogen does not emit a red line, but it has a yellow line and a magenta line, and the combination of these produces the sensation of red. 
C)  Ionized hydrogen cannot be detected directly, so CO is used as a tracer, and CO produces a red line. 
D)  Neutral hydrogen atoms are formed temporarily in the plasma of an H II region, and they emit the red Hα line.

Question 9

What name is given to a young, cool star (spectral class G, K, or M) that is ejecting gas into the interstellar medium?

Accepted Answer

A)  Cepheid variable 
B)  flare star 
C)  RR Lyrae star 
D)  T Tauri star 
A)  Cepheid variable 
B)  flare star 
C)  RR Lyrae star 
D)  T Tauri star

Question 10

Which of these stars are metal-rich?

Accepted Answer

A)  Population I stars 
B)  very old stars 
C)  Population II stars 
D)  globular cluster stars 
A)  Population I stars 
B)  very old stars 
C)  Population II stars 
D)  globular cluster stars

Question 11

The spectrum of stars in an open cluster is found to contain spectral lines from many heavy elements; the stars are known as "metal-rich." What is the source of these heavy elements?

Accepted Answer

A)  fusion reactions on the very hot surfaces of these stars 
B)  The heavy element content of these stars is not enhanced but the hydrogen and helium content has been depleted by intense stellar winds made up preferentially of these light elements. 
C)  fusion reactions in the star cores, carried to the surface by convection 
D)  interstellar medium, which originated in explosions of stars earlier in history that had manufactured heavy elements by nuclear fusion 
A)  fusion reactions on the very hot surfaces of these stars 
B)  The heavy element content of these stars is not enhanced but the hydrogen and helium content has been depleted by intense stellar winds made up preferentially of these light elements. 
C)  fusion reactions in the star cores, carried to the surface by convection 
D)  interstellar medium, which originated in explosions of stars earlier in history that had manufactured heavy elements by nuclear fusion

Question 12

How long does a star of 3 times the Sun's mass live compared with the lifetime of the Sun?

Accepted Answer

A)  A star of 3 times the Sun's mass lives about 1/3 as long as the Sun. 
B)  A star of 3 times the Sun's mass lives about 1/20 as long as the Sun. 
C)  A star of 3 times the Sun's mass lives about 3 times as long as the Sun. 
D)  A star of 3 times the Sun's mass lives about 1/500 as long as the Sun. 
A)  A star of 3 times the Sun's mass lives about 1/3 as long as the Sun. 
B)  A star of 3 times the Sun's mass lives about 1/20 as long as the Sun. 
C)  A star of 3 times the Sun's mass lives about 3 times as long as the Sun. 
D)  A star of 3 times the Sun's mass lives about 1/500 as long as the Sun.

Question 13

Accretion of matter in an interstellar cloud leads to

Accepted Answer

A)  a supernova explosion, since accretion is a nuclear process. 
B)  explosion of this matter when it is attracted to and falls onto the surfaces of stars. 
C)  the formation of molecules from atomic gases. 
D)  a protostar. 
A)  a supernova explosion, since accretion is a nuclear process. 
B)  explosion of this matter when it is attracted to and falls onto the surfaces of stars. 
C)  the formation of molecules from atomic gases. 
D)  a protostar.

Question 14

What is believed to be the MOST important factor determining whether a collapsing region (dense core) in an interstellar cloud becomes a single-star or a multiple-star system?

Accepted Answer

A)  fraction of heavy elements in the cloud 
B)  temperature 
C)  mass of the collapsing region 
D)  amount of rotation (spin) 
A)  fraction of heavy elements in the cloud 
B)  temperature 
C)  mass of the collapsing region 
D)  amount of rotation (spin)

Question 15

RR Lyrae stars are

Accepted Answer

A)  pulsating stars that vary regularly, all with periods of less than 1 day. 
B)  rotating neutron stars with very rapid and regular brightness fluctuations. 
C)  eclipsing binary stars. 
D)  pulsating stars that vary irregularly, with periods of several hundred days. 
A)  pulsating stars that vary regularly, all with periods of less than 1 day. 
B)  rotating neutron stars with very rapid and regular brightness fluctuations. 
C)  eclipsing binary stars. 
D)  pulsating stars that vary irregularly, with periods of several hundred days.

Question 16

The distinct blue color of the nebulosity around stars in young clusters such as the Pleiades (see Figure 13-4 in the text) is caused by

Accepted Answer

A)  atoms of gas emitting light by fluorescence, having been excited by ultraviolet radiation from hot stars. 
B)  light emitted by interstellar gases but Doppler-shifted by motion toward the observer. 
C)  starlight reflected by blue-colored interstellar material. 
D)  starlight scattered and reflected by small dust grains in the interstellar material. 
A)  atoms of gas emitting light by fluorescence, having been excited by ultraviolet radiation from hot stars. 
B)  light emitted by interstellar gases but Doppler-shifted by motion toward the observer. 
C)  starlight reflected by blue-colored interstellar material. 
D)  starlight scattered and reflected by small dust grains in the interstellar material.

Question 17

Open clusters are NOT

Accepted Answer

A)  gravitationally bound. 
B)  the result of star formation within a single giant molecular cloud. 
C)  loose groupings of stars of a wide range of ages. 
D)  known to contain more than about 100 stars. 
A)  gravitationally bound. 
B)  the result of star formation within a single giant molecular cloud. 
C)  loose groupings of stars of a wide range of ages. 
D)  known to contain more than about 100 stars.

Question 18

What appears to be the limit to the amount of mass that can accumulate as a star before energy from intense nuclear fusion, emitted in the form of electromagnetic radiation, ejects further mass away from the star?

Accepted Answer

A)  at least 150 solar masses, but not more than several hundred solar masses 
B)  only about 3 solar masses, hence the similarity of all observed stars 
C)  10 solar masses 
D)  106 solar masses 
A)  at least 150 solar masses, but not more than several hundred solar masses 
B)  only about 3 solar masses, hence the similarity of all observed stars 
C)  10 solar masses 
D)  106 solar masses

Question 19

The apparent reddening of light from stars after its passage through the interstellar medium is caused by

Accepted Answer

A)  the additional contribution to this starlight by emission from hydrogen gas in the interstellar medium. 
B)  preferential scattering of blue starlight by dust grains. 
C)  Zeeman shift of the light by the powerful magnetic fields existing within the interstellar medium. 
D)  scattering of this light from rapidly moving material; the light is Doppler-shifted toward the red end of the spectrum. 
A)  the additional contribution to this starlight by emission from hydrogen gas in the interstellar medium. 
B)  preferential scattering of blue starlight by dust grains. 
C)  Zeeman shift of the light by the powerful magnetic fields existing within the interstellar medium. 
D)  scattering of this light from rapidly moving material; the light is Doppler-shifted toward the red end of the spectrum.

Question 20

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

Which range of electromagnetic radiation is MOST useful for observing newborn protostars in their gas and dust nebulae?

What is unusual about main-sequence stars that are about 75 percent the mass of the Sun?

Electron degeneracy, which is a result of the Pauli exclusion principle, is important in

What is a typical size for a giant molecular cloud?

At what stage in its life does a star pass through the protostar phase?

At what temperature do nuclear reactions begin in the core of a pre-main-sequence star?

Evidence of massive amounts of hydrogen gas surrounding some young, hot stars comes from

Why do many H II regions glow with a prominent red color?

What name is given to a young, cool star (spectral class G, K, or M) that is ejecting gas into the interstellar medium?

Which of these stars are metal-rich?

The spectrum of stars in an open cluster is found to contain spectral lines from many heavy elements; the stars are known as "metal-rich." What is the source of these heavy elements?

How long does a star of 3 times the Sun's mass live compared with the lifetime of the Sun?

Accretion of matter in an interstellar cloud leads to

What is believed to be the MOST important factor determining whether a collapsing region (dense core) in an interstellar cloud becomes a single-star or a multiple-star system?

RR Lyrae stars are

The distinct blue color of the nebulosity around stars in young clusters such as the Pleiades (see Figure 13-4 in the text) is caused by

Open clusters are NOT

What appears to be the limit to the amount of mass that can accumulate as a star before energy from intense nuclear fusion, emitted in the form of electromagnetic radiation, ejects further mass away from the star?

The apparent reddening of light from stars after its passage through the interstellar medium is caused by

T Tauri stars are at what stage of stellar evolution?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

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Exam 13: The Lives of Stars From Birth Through Middle Age

Which range of electromagnetic radiation is MOST useful for observing newborn protostars in their gas and dust nebulae?

What is unusual about main-sequence stars that are about 75 percent the mass of the Sun?

Electron degeneracy, which is a result of the Pauli exclusion principle, is important in

What is a typical size for a giant molecular cloud?

At what stage in its life does a star pass through the protostar phase?

At what temperature do nuclear reactions begin in the core of a pre-main-sequence star?

Evidence of massive amounts of hydrogen gas surrounding some young, hot stars comes from

Why do many H II regions glow with a prominent red color?

What name is given to a young, cool star (spectral class G, K, or M) that is ejecting gas into the interstellar medium?

Which of these stars are metal-rich?

The spectrum of stars in an open cluster is found to contain spectral lines from many heavy elements; the stars are known as "metal-rich." What is the source of these heavy elements?

How long does a star of 3 times the Sun's mass live compared with the lifetime of the Sun?

Accretion of matter in an interstellar cloud leads to

What is believed to be the MOST important factor determining whether a collapsing region (dense core) in an interstellar cloud becomes a single-star or a multiple-star system?

RR Lyrae stars are

The distinct blue color of the nebulosity around stars in young clusters such as the Pleiades (see Figure 13-4 in the text) is caused by

Open clusters are NOT

What appears to be the limit to the amount of mass that can accumulate as a star before energy from intense nuclear fusion, emitted in the form of electromagnetic radiation, ejects further mass away from the star?

The apparent reddening of light from stars after its passage through the interstellar medium is caused by

T Tauri stars are at what stage of stellar evolution?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters