Question 1

Stars on the main sequence obey a mass-luminosity relation. According to this relation,

Accepted Answer

A)  the lower the mass, the higher the luminosity 
B)  if you double the mass, you get double the luminosity 
C)  luminosity is proportional to mass to the fourth power (luminosity increases strongly with mass) 
D)  bright stars have more mass around them in the form of planets, comets, and asteroids 
E)  the brightest stars are made of such light materials they hardly have any mass at all
Section 18.3: Diameters of Stars 
A)  the lower the mass, the higher the luminosity 
B)  if you double the mass, you get double the luminosity 
C)  luminosity is proportional to mass to the fourth power (luminosity increases strongly with mass) 
D)  bright stars have more mass around them in the form of planets, comets, and asteroids 
E)  the brightest stars are made of such light materials they hardly have any mass at all
Section 18.3: Diameters of Stars

Question 2

Which law do astronomers use to determine the masses of the stars in a spectroscopic binary system?

Accepted Answer

A)  Wien's Law 
B)  Kepler's Third Law 
C)  Stefan-Boltzmann Law 
D)  Hubble's Law 
E)  Jenny Craig's Law 
A)  Wien's Law 
B)  Kepler's Third Law 
C)  Stefan-Boltzmann Law 
D)  Hubble's Law 
E)  Jenny Craig's Law

Question 3

Imagine that powerful telescopes in the future give us a truly representative sampling of all the stars in the Sun's cosmic neighborhood. Where on the H-R diagram would most of the stars in our immediate vicinity lie?

Accepted Answer

A)  in the upper right, among the supergiants 
B)  in the upper left, among the bright main sequence stars 
C)  in the middle of the main sequence, roughly where the Sun is 
D)  in the lower left, among the white dwarfs 
E)  in the lower right, among the least luminous main sequence stars 
A)  in the upper right, among the supergiants 
B)  in the upper left, among the bright main sequence stars 
C)  in the middle of the main sequence, roughly where the Sun is 
D)  in the lower left, among the white dwarfs 
E)  in the lower right, among the least luminous main sequence stars

Question 4

Astronomers identify the main sequence on the H-R diagram with what activity in the course of a star's life?

Accepted Answer

A)  forming from a reservoir of cosmic material 
B)  fusing hydrogen into helium in their cores 
C)  letting go of a huge outer layer 
D)  dying 
E)  you can't fool me; so many stars are on the main sequence that there is no special stage in a star's life that can be identified with it 
A)  forming from a reservoir of cosmic material 
B)  fusing hydrogen into helium in their cores 
C)  letting go of a huge outer layer 
D)  dying 
E)  you can't fool me; so many stars are on the main sequence that there is no special stage in a star's life that can be identified with it

Question 5

Which of the following statements about spectroscopic binary stars is FALSE?

Accepted Answer

A)  visually we can only see one star 
B)  some of the lines in the spectrum are double, with the spacing changing over time 
C)  an analysis of the ways the lines in the spectrum change allows us to calculate the star's distance directly 
D)  we can use the spectrum to determine the sum of the masses of the two stars 
E)  we can often use the changes in the positions of the spectral lines to measure the radial velocity of the stars in the system 
A)  visually we can only see one star 
B)  some of the lines in the spectrum are double, with the spacing changing over time 
C)  an analysis of the ways the lines in the spectrum change allows us to calculate the star's distance directly 
D)  we can use the spectrum to determine the sum of the masses of the two stars 
E)  we can often use the changes in the positions of the spectral lines to measure the radial velocity of the stars in the system

Question 6

A star that is quite hot and has a very small radius compared to most stars is called

Accepted Answer

A)  a main-sequence star 
B)  an O-type star 
C)  a red giant 
D)  a white dwarf 
E)  an M-type star 
A)  a main-sequence star 
B)  an O-type star 
C)  a red giant 
D)  a white dwarf 
E)  an M-type star

Question 7

Stars that lie in different places on the main sequence of the H-R diagram differ from each other mainly by having different:

Accepted Answer

A)  compositions 
B)  internal structure 
C)  masses 
D)  radial velocities 
E)  ways that they formed 
A)  compositions 
B)  internal structure 
C)  masses 
D)  radial velocities 
E)  ways that they formed

Question 8

Stars that do not have what it takes to succeed as a star (i.e. do not have enough mass to fuse hydrogen into helium at their centers) are called:

Accepted Answer

A)  extras 
B)  red giants 
C)  spectroscopic stars 
D)  brown dwarfs 
E)  main sequence stars 
A)  extras 
B)  red giants 
C)  spectroscopic stars 
D)  brown dwarfs 
E)  main sequence stars

Question 9

Most of the really bright stars in our sky are NOT among the stars that are very close to us. Why then do they look so bright to us?

Accepted Answer

A)  we see them in crowded regions of stars, which give us the impression that the stars there are brighter than they really are 
B)  all the brightest stars are red, and red color is much easier to see against the black night sky 
C)  these stars vary in brightness (flashing brighter and dimmer) and are thus easier to notice 
D)  these stars are intrinsically so luminous, that they can easily be seen even across great distances 
E)  actually, this is just an optical illusion; all stars are really the same brightness 
A)  we see them in crowded regions of stars, which give us the impression that the stars there are brighter than they really are 
B)  all the brightest stars are red, and red color is much easier to see against the black night sky 
C)  these stars vary in brightness (flashing brighter and dimmer) and are thus easier to notice 
D)  these stars are intrinsically so luminous, that they can easily be seen even across great distances 
E)  actually, this is just an optical illusion; all stars are really the same brightness

Stars on the main sequence obey a mass-luminosity relation. According to this relation,

Which law do astronomers use to determine the masses of the stars in a spectroscopic binary system?

Imagine that powerful telescopes in the future give us a truly representative sampling of all the stars in the Sun's cosmic neighborhood. Where on the H-R diagram would most of the stars in our immediate vicinity lie?

Astronomers identify the main sequence on the H-R diagram with what activity in the course of a star's life?

Which of the following statements about spectroscopic binary stars is FALSE?

A star that is quite hot and has a very small radius compared to most stars is called

Stars that lie in different places on the main sequence of the H-R diagram differ from each other mainly by having different:

Stars that do not have what it takes to succeed as a star (i.e. do not have enough mass to fuse hydrogen into helium at their centers) are called:

Most of the really bright stars in our sky are NOT among the stars that are very close to us. Why then do they look so bright to us?

Science and the Universe: a Brief Tour

Observing the Sky: the Birth of Astronomy

Orbits and Gravity

Earth, Moon, and Sky

Radiation and Spectra

Astronomical Instruments

Other Worlds: an Introduction to the Solar System

Earth As a Planet

Cratered Worlds: the Moon and Mercury

Earthlike Planets: Venus and Mars

The Giant Planets

Rings, Moons, and Pluto

Comets and Asteroids: Debris of the Solar System

Cosmic Samples and the Origin of the Solar System

The Sun: a Garden-Variety Star

The Sun: a Nuclear Powerhouse

Analyzing Starlight

Celestial Distances

Between the Stars

The Birth of Stars and the Discovery of Planets Outside the Solar System

Stars From Adolescence to Old Age

The Death of Stars

Black Holes and Curved Space-Time

The Milky Way Galaxy

Galaxies

Active Galaxies, Quasars, and Supermassive Black Holes

The Evolution and Distribution of Galaxies

The Big Bang

Life in the Universe

Filters

Exam 18: The Stars: a Celestial Census

Stars on the main sequence obey a mass-luminosity relation. According to this relation,

Which law do astronomers use to determine the masses of the stars in a spectroscopic binary system?

Imagine that powerful telescopes in the future give us a truly representative sampling of all the stars in the Sun's cosmic neighborhood. Where on the H-R diagram would most of the stars in our immediate vicinity lie?

Astronomers identify the main sequence on the H-R diagram with what activity in the course of a star's life?

Which of the following statements about spectroscopic binary stars is FALSE?

A star that is quite hot and has a very small radius compared to most stars is called

Stars that lie in different places on the main sequence of the H-R diagram differ from each other mainly by having different:

Stars that do not have what it takes to succeed as a star (i.e. do not have enough mass to fuse hydrogen into helium at their centers) are called:

Most of the really bright stars in our sky are NOT among the stars that are very close to us. Why then do they look so bright to us?

Science and the Universe: a Brief Tour

Observing the Sky: the Birth of Astronomy

Orbits and Gravity

Earth, Moon, and Sky

Radiation and Spectra

Astronomical Instruments

Other Worlds: an Introduction to the Solar System

Earth As a Planet

Cratered Worlds: the Moon and Mercury

Earthlike Planets: Venus and Mars

The Giant Planets

Rings, Moons, and Pluto

Comets and Asteroids: Debris of the Solar System

Cosmic Samples and the Origin of the Solar System

The Sun: a Garden-Variety Star

The Sun: a Nuclear Powerhouse

Analyzing Starlight

Celestial Distances

Between the Stars

The Birth of Stars and the Discovery of Planets Outside the Solar System

Stars From Adolescence to Old Age

The Death of Stars

Black Holes and Curved Space-Time

The Milky Way Galaxy

Galaxies

Active Galaxies, Quasars, and Supermassive Black Holes

The Evolution and Distribution of Galaxies

The Big Bang

Life in the Universe

Filters