Question 1

What happens to the helium-rich core of a star after the core runs out of hydrogen?

Accepted Answer

A)  The core cools down and contracts. 
B)  The core expands and cools down. 
C)  The core heats up and expands. 
D)  The core contracts and heats up. 
A)  The core cools down and contracts. 
B)  The core expands and cools down. 
C)  The core heats up and expands. 
D)  The core contracts and heats up.

Question 2

The zero-age main sequence describes the sequence of stars in the Hertzsprung-Russell diagram that:

Accepted Answer

A)  contain no processed elements (elements heavier than hydrogen or helium). 
B)  are just beginning to convert helium into carbon in their cores. 
C)  have just collapsed from the interstellar medium. 
D)  have just reached the main sequence. 
A)  contain no processed elements (elements heavier than hydrogen or helium). 
B)  are just beginning to convert helium into carbon in their cores. 
C)  have just collapsed from the interstellar medium. 
D)  have just reached the main sequence.

Question 3

A star is observed to be on or close to the main-sequence region of the Hertzsprung-Russell diagram.What particular feature of stellar behavior can be inferred by this observation?

Accepted Answer

A)  The star is generating internal energy by hydrogen fusion. 
B)  The star is generating energy by helium fusion, having stopped hydrogen "burning." 
C)  The star is slowly shrinking and thereby releasing gravitational potential energy as it slides down the main sequence from top left to bottom right across the H-R diagram. 
D)  Stars that have reached the main sequence have ceased nuclear "burning" and are simply cooling down by emitting radiation. 
A)  The star is generating internal energy by hydrogen fusion. 
B)  The star is generating energy by helium fusion, having stopped hydrogen "burning." 
C)  The star is slowly shrinking and thereby releasing gravitational potential energy as it slides down the main sequence from top left to bottom right across the H-R diagram. 
D)  Stars that have reached the main sequence have ceased nuclear "burning" and are simply cooling down by emitting radiation.

Question 4

What is the Pauli exclusion principle?

Accepted Answer

A)  Photons of less than a certain wavelength cannot eject electrons from a metal. 
B)  Two identical particles cannot occupy the same place at the same time. 
C)  Two different atoms cannot have the same energy levels. 
D)  Two identical photons cannot be absorbed by the same atom. 
A)  Photons of less than a certain wavelength cannot eject electrons from a metal. 
B)  Two identical particles cannot occupy the same place at the same time. 
C)  Two different atoms cannot have the same energy levels. 
D)  Two identical photons cannot be absorbed by the same atom.

Question 5

The light from a distant cloud of gas and dust looks distinctly red to the unaided eye.When a spectrum is taken,the red color is found to come from a single,bright spectral line.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 6

How much time does it take for a 1-solar-mass protostar to finish accreting mass from the interstellar cloud?

Accepted Answer

A)  10,000 years 
B)  100,000 years 
C)  1 billion years 
D)  10 million years 
A)  10,000 years 
B)  100,000 years 
C)  1 billion years 
D)  10 million years

Question 7

Suppose that an astronomical observatory announces the discovery of an object with about 50 times the mass of Jupiter.Since this mass is not enough for the object to be a star,what name would the observatory apply to the object?

Accepted Answer

A)  red dwarf 
B)  infrared dwarf 
C)  brown dwarf 
D)  white dwarf 
A)  red dwarf 
B)  infrared dwarf 
C)  brown dwarf 
D)  white dwarf

Question 8

In order to produce protoplanets around a new star within a condensing interstellar cloud,a necessary condition seems to be that the cloud must:

Accepted Answer

A)  be rotating. 
B)  have a relatively high temperature. 
C)  have no rotational motion at all. 
D)  contain a high fraction of its mass as dust. 
A)  be rotating. 
B)  have a relatively high temperature. 
C)  have no rotational motion at all. 
D)  contain a high fraction of its mass as dust.

Question 9

Which major perturbation can occur to a close binary system and radically alter the evolution and behavior of the two individual stars?

Accepted Answer

A)  heating of the localized areas of the atmosphere of one star by its companion 
B)  transfer of matter from one star to its companion 
C)  gravitational disturbance of one star's motion by its companion, forcing it to move in an orbit 
D)  eclipse of the light from one star by the other when viewed from Earth 
A)  heating of the localized areas of the atmosphere of one star by its companion 
B)  transfer of matter from one star to its companion 
C)  gravitational disturbance of one star's motion by its companion, forcing it to move in an orbit 
D)  eclipse of the light from one star by the other when viewed from Earth

Question 10

Which statement about a globular cluster is NOT true?

Accepted Answer

A)  A globular cluster has a round shape. 
B)  A globular cluster can contain up to 1 million stars. 
C)  A globular cluster contains many main-sequence stars. 
D)  A globular cluster contains both high- and low-mass stars on the main sequence. 
A)  A globular cluster has a round shape. 
B)  A globular cluster can contain up to 1 million stars. 
C)  A globular cluster contains many main-sequence stars. 
D)  A globular cluster contains both high- and low-mass stars on the main sequence.

Question 11

Which object is LEAST massive?

Accepted Answer

A)  a brown dwarf 
B)  the Sun 
C)  a giant molecular cloud 
D)  a T Tauri star 
A)  a brown dwarf 
B)  the Sun 
C)  a giant molecular cloud 
D)  a T Tauri star

Question 12

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 
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 
B)  only about 3 solar masses, hence the similarity of all observed stars 
C)  10 solar masses 
D)  10⁶ solar masses

Question 13

The Pleiades cluster consists of a number of bright stars wrapped in a cloud of gas and dust that appears blue.This cluster is an example of a:

Accepted Answer

A)  giant molecular cloud. 
B)  dark nebula. 
C)  reflection nebula. 
D)  stellar "nursery." 
A)  giant molecular cloud. 
B)  dark nebula. 
C)  reflection nebula. 
D)  stellar "nursery."

Question 14

What is the BEST way to estimate the age of a star cluster?

Accepted Answer

A)  Plot the stars on a Hertzsprung-Russell diagram and see which stars are still on the main sequence. 
B)  Measure the motions of the stars in the cluster and compare the measurements with theoretical models. 
C)  Measure the heavy element abundance for the stars in the cluster. 
D)  Count the number of T Tauri stars in the cluster. 
A)  Plot the stars on a Hertzsprung-Russell diagram and see which stars are still on the main sequence. 
B)  Measure the motions of the stars in the cluster and compare the measurements with theoretical models. 
C)  Measure the heavy element abundance for the stars in the cluster. 
D)  Count the number of T Tauri stars in the cluster.

Question 15

Under what conditions does electron degeneracy occur?

Accepted Answer

A)  when electrons become too closely crowded together 
B)  when thermonuclear reactions release more electrons than protons 
C)  when electrons and positrons annihilate, releasing energy 
D)  when ultraviolet light from hot, young O and B stars ionizes the interstellar medium 
A)  when electrons become too closely crowded together 
B)  when thermonuclear reactions release more electrons than protons 
C)  when electrons and positrons annihilate, releasing energy 
D)  when ultraviolet light from hot, young O and B stars ionizes the interstellar medium

Question 16

Which fact referring to stars in a cluster is NOT particularly useful for interpreting the evolution of these stars?

Accepted Answer

A)  The stars are all at the same distance from Earth, so we measure true intrinsic brightnesses of the stars. 
B)  The stars all formed at about the same time. 
C)  The stars formed from the same mix of chemical elements but with a mix of original masses. 
D)  The majority of the material in these stars is hydrogen. 
A)  The stars are all at the same distance from Earth, so we measure true intrinsic brightnesses of the stars. 
B)  The stars all formed at about the same time. 
C)  The stars formed from the same mix of chemical elements but with a mix of original masses. 
D)  The majority of the material in these stars is hydrogen.

Question 17

Which star would you classify as a Population II star?

Accepted Answer

A)  a star with very low abundance of heavy elements 
B)  a star in an open star cluster 
C)  a star with approximately the same abundance of heavy elements that we find in the Sun 
D)  a star with much higher abundance of heavy elements than we find in the Sun 
A)  a star with very low abundance of heavy elements 
B)  a star in an open star cluster 
C)  a star with approximately the same abundance of heavy elements that we find in the Sun 
D)  a star with much higher abundance of heavy elements than we find in the Sun

Question 18

A star cluster at a great distance from the Sun appears to be fainter than a similar star cluster at a closer distance.Part of this is the expected result from the inverse square law,but the distant cluster will also appear fainter than expected by distance alone because:

Accepted Answer

A)  the photons of light become "tired" and appear less bright as they travel. 
B)  the cosmological redshift has moved some of the light into the infrared spectral region. 
C)  star clusters are systematically smaller and hence less bright the farther they are from the galactic center and hence from the Sun. 
D)  light is scattered and absorbed by interstellar dust and gas between distant clusters and Earth. 
A)  the photons of light become "tired" and appear less bright as they travel. 
B)  the cosmological redshift has moved some of the light into the infrared spectral region. 
C)  star clusters are systematically smaller and hence less bright the farther they are from the galactic center and hence from the Sun. 
D)  light is scattered and absorbed by interstellar dust and gas between distant clusters and Earth.

Question 19

How do the stars in a star cluster change with time?

Accepted Answer

A)  All stars in a cluster evolve at the same rate. 
B)  The stars with the greatest heavy element content evolve the most quickly. 
C)  The lowest-mass stars evolve the most quickly. 
D)  The highest-mass stars evolve the most quickly. 
A)  All stars in a cluster evolve at the same rate. 
B)  The stars with the greatest heavy element content evolve the most quickly. 
C)  The lowest-mass stars evolve the most quickly. 
D)  The highest-mass stars evolve the most quickly.

Question 20

Which astronomical object or system is likely to be the oldest?

Accepted Answer

A)  a T Tauri star 
B)  Pleiades 
C)  the Sun 
D)  a globular cluster 
A)  a T Tauri star 
B)  Pleiades 
C)  the Sun 
D)  a globular cluster

What happens to the helium-rich core of a star after the core runs out of hydrogen?

The zero-age main sequence describes the sequence of stars in the Hertzsprung-Russell diagram that:

A star is observed to be on or close to the main-sequence region of the Hertzsprung-Russell diagram.What particular feature of stellar behavior can be inferred by this observation?

What is the Pauli exclusion principle?

The light from a distant cloud of gas and dust looks distinctly red to the unaided eye.When a spectrum is taken,the red color is found to come from a single,bright spectral line.Thus the red color in this situation is due to:

How much time does it take for a 1-solar-mass protostar to finish accreting mass from the interstellar cloud?

Suppose that an astronomical observatory announces the discovery of an object with about 50 times the mass of Jupiter.Since this mass is not enough for the object to be a star,what name would the observatory apply to the object?

In order to produce protoplanets around a new star within a condensing interstellar cloud,a necessary condition seems to be that the cloud must:

Which major perturbation can occur to a close binary system and radically alter the evolution and behavior of the two individual stars?

Which statement about a globular cluster is NOT true?

Which object is LEAST massive?

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 Pleiades cluster consists of a number of bright stars wrapped in a cloud of gas and dust that appears blue.This cluster is an example of a:

What is the BEST way to estimate the age of a star cluster?

Under what conditions does electron degeneracy occur?

Which fact referring to stars in a cluster is NOT particularly useful for interpreting the evolution of these stars?

Which star would you classify as a Population II star?

A star cluster at a great distance from the Sun appears to be fainter than a similar star cluster at a closer distance.Part of this is the expected result from the inverse square law,but the distant cluster will also appear fainter than expected by distance alone because:

How do the stars in a star cluster change with time?

Which astronomical object or system is likely to be the oldest?

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

What happens to the helium-rich core of a star after the core runs out of hydrogen?

The zero-age main sequence describes the sequence of stars in the Hertzsprung-Russell diagram that:

A star is observed to be on or close to the main-sequence region of the Hertzsprung-Russell diagram.What particular feature of stellar behavior can be inferred by this observation?

What is the Pauli exclusion principle?

The light from a distant cloud of gas and dust looks distinctly red to the unaided eye.When a spectrum is taken,the red color is found to come from a single,bright spectral line.Thus the red color in this situation is due to:

How much time does it take for a 1-solar-mass protostar to finish accreting mass from the interstellar cloud?

Suppose that an astronomical observatory announces the discovery of an object with about 50 times the mass of Jupiter.Since this mass is not enough for the object to be a star,what name would the observatory apply to the object?

In order to produce protoplanets around a new star within a condensing interstellar cloud,a necessary condition seems to be that the cloud must:

Which major perturbation can occur to a close binary system and radically alter the evolution and behavior of the two individual stars?

Which statement about a globular cluster is NOT true?

Which object is LEAST massive?

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 Pleiades cluster consists of a number of bright stars wrapped in a cloud of gas and dust that appears blue.This cluster is an example of a:

What is the BEST way to estimate the age of a star cluster?

Under what conditions does electron degeneracy occur?

Which fact referring to stars in a cluster is NOT particularly useful for interpreting the evolution of these stars?

Which star would you classify as a Population II star?

A star cluster at a great distance from the Sun appears to be fainter than a similar star cluster at a closer distance.Part of this is the expected result from the inverse square law,but the distant cluster will also appear fainter than expected by distance alone because:

How do the stars in a star cluster change with time?

Which astronomical object or system is likely to be the oldest?

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