Question 1

If you compare two stars,the one with the _____ must have the greater luminosity.

Accepted Answer

A)  larger radius 
B)  higher surface temperature 
C)  smaller absolute magnitude 
D)  larger surface area 
A)  larger radius 
B)  higher surface temperature 
C)  smaller absolute magnitude 
D)  larger surface area

Question 2

The star Alphard has an apparent magnitude of 2.0,and the star Megrez has an apparent magnitude of 3.3.The only thing that can be said with certainty about Alphard is that it is _____ than Megrez.

Accepted Answer

A)  brighter, as seen in Earth's sky, 
B)  more luminous 
C)  fainter, as seen in Earth's sky, 
D)  closer to Earth 
A)  brighter, as seen in Earth's sky, 
B)  more luminous 
C)  fainter, as seen in Earth's sky, 
D)  closer to Earth

Question 3

What is parallax?

Accepted Answer

A)  the distance to an object, measured in parsecs 
B)  the angle taken up by the size (e.g., diameter) of an object, as seen by an observer 
C)  the shift in angular position of an object as it moves in space 
D)  the apparent shift in position of an object as the observer moves 
A)  the distance to an object, measured in parsecs 
B)  the angle taken up by the size (e.g., diameter) of an object, as seen by an observer 
C)  the shift in angular position of an object as it moves in space 
D)  the apparent shift in position of an object as the observer moves

Question 4

Which atom or ion produces strong absorption lines in the spectra of stars with relatively cool surface temperatures?

Accepted Answer

A)  TiO, molecules of titanium oxide 
B)  Mg II, ionized magnesium 
C)  Ca II, ionized calcium 
D)  He I, neutral helium 
A)  TiO, molecules of titanium oxide 
B)  Mg II, ionized magnesium 
C)  Ca II, ionized calcium 
D)  He I, neutral helium

Question 5

Using the Hertzsprung-Russell diagram and the mass-luminosity relationship for main-sequence stars (Figure 10-14 of Comins,Discovering the Essential Universe,6th ed.),determine which type of main-sequence stars would have the highest mass.

Accepted Answer

A)  M 
B)  A 
C)  O 
D)  G 
A)  M 
B)  A 
C)  O 
D)  G

Question 6

The difference in the brightness of a star as seen through two different colored filters,for example,blue and yellow,is directly related to which stellar property?

Accepted Answer

A)  distance from Earth 
B)  luminosity 
C)  surface temperature 
D)  radius 
A)  distance from Earth 
B)  luminosity 
C)  surface temperature 
D)  radius

Question 7

Two stars in our sky have the same apparent brightness.If neither of them is hidden behind gas or dust clouds,then we know that they:

Accepted Answer

A)  must be at the same distance from us. 
B)  may be at different distances, in which case the nearer one must have the greater luminosity. 
C)  may be at different distances, in which case the farther one must have the greater luminosity. 
D)  must have the same temperature. 
A)  must be at the same distance from us. 
B)  may be at different distances, in which case the nearer one must have the greater luminosity. 
C)  may be at different distances, in which case the farther one must have the greater luminosity. 
D)  must have the same temperature.

Question 8

The first accurate measurement of stellar parallax was made in:

Accepted Answer

A)  the fourth century b.c.e. 
B)  1721. 
C)  1838. 
D)  1927. 
A)  the fourth century b.c.e. 
B)  1721. 
C)  1838. 
D)  1927.

Question 9

How are white dwarfs treated in the luminosity class definitions?

Accepted Answer

A)  They are considered a subgroup of main sequence stars, class Vb. 
B)  They are class VI. 
C)  They are not given a classification because they have not yet begun to produce energy by nuclear fusion. 
D)  They are not given a classification because they no longer create energy by nuclear fusion. 
A)  They are considered a subgroup of main sequence stars, class Vb. 
B)  They are class VI. 
C)  They are not given a classification because they have not yet begun to produce energy by nuclear fusion. 
D)  They are not given a classification because they no longer create energy by nuclear fusion.

Question 10

A star of apparent magnitude +2.1 appears _____ than a star of apparent magnitude -1.2.

Accepted Answer

A)  farther away 
B)  fainter 
C)  brighter 
D)  either brighter or fainter, depending on the distance to the stars, 
A)  farther away 
B)  fainter 
C)  brighter 
D)  either brighter or fainter, depending on the distance to the stars,

Question 11

Star A has luminosity LA = 100 L⊙ and it is 1000 pc away.Star B has the same luminosity as the Sun,L⊙,and it is 100 pc away.What can you say about the brightnesses of these two stars?

Accepted Answer

A)  Star A is brighter than star B. 
B)  Star B is brighter than star A. 
C)  Star A and star B have the same brightness. 
D)  It is not possible to answer the question without knowing L⊙, the luminosity of the Sun. 
A)  Star A is brighter than star B. 
B)  Star B is brighter than star A. 
C)  Star A and star B have the same brightness. 
D)  It is not possible to answer the question without knowing L⊙, the luminosity of the Sun.

Question 12

A particular star appears approximately equally bright when viewed through a blue filter and through a yellow filter.What is the approximate surface temperature of this star? (See Figure 10-4,Comins,Discovering the Essential Universe,6th ed.)

Accepted Answer

A)  6000 K 
B)  12,000 K 
C)  3000 K 
D)  It is not possible for a star to be equally bright at two different wavelengths. 
A)  6000 K 
B)  12,000 K 
C)  3000 K 
D)  It is not possible for a star to be equally bright at two different wavelengths.

Question 13

Which is NOT needed to determine individual masses in a binary star system?

Accepted Answer

A)  the distance to the binary system 
B)  the plane of the orbit of the two stars 
C)  the relative sizes of the orbits of the two stars 
D)  the absolute magnitude of at least one star 
A)  the distance to the binary system 
B)  the plane of the orbit of the two stars 
C)  the relative sizes of the orbits of the two stars 
D)  the absolute magnitude of at least one star

Question 14

Two stars in a binary system orbit around a common point that is:

Accepted Answer

A)  exactly midway between the two stars. 
B)  closer to the less massive star. 
C)  closer to the more massive star. 
D)  inside one of the stars. 
A)  exactly midway between the two stars. 
B)  closer to the less massive star. 
C)  closer to the more massive star. 
D)  inside one of the stars.

Question 15

A star that is 100 pc distant from Earth has an apparent magnitude of m +2.5.According to the equation in Discovery 10-2 in Comins,Discovering the Essential Universe,6th ed.,what is its absolute magnitude?

Accepted Answer

A)  -7.5 
B)  +7.5 
C)  -2.5 
D)  -47.5 
A)  -7.5 
B)  +7.5 
C)  -2.5 
D)  -47.5

Question 16

What proportion of visible stars in our nighttime sky are members of multiple-star systems,such as binary stars?

Accepted Answer

A)  less than 1% 
B)  2/3, or almost 70% 
C)  only about 1/4, or 25% 
D)  close to 100% 
A)  less than 1% 
B)  2/3, or almost 70% 
C)  only about 1/4, or 25% 
D)  close to 100%

Question 17

The technique called photometry in stellar astronomy is the measurement of the:

Accepted Answer

A)  arrival times of photons from variable and pulsating stars to determine accurately the pulsation or rotation periods of these stars. 
B)  intensity of light from stars through several limited-bandpass filters from which surface temperature, variability, luminosity, and so on of stars can be determined. 
C)  relative absorption of light by different atoms and molecules in high-resolution spectra of starlight, from which stellar temperatures can be estimated. 
D)  precise positions and relative motions of stars in the Galaxy, from which galactic structure and overall rotation can be determined. 
A)  arrival times of photons from variable and pulsating stars to determine accurately the pulsation or rotation periods of these stars. 
B)  intensity of light from stars through several limited-bandpass filters from which surface temperature, variability, luminosity, and so on of stars can be determined. 
C)  relative absorption of light by different atoms and molecules in high-resolution spectra of starlight, from which stellar temperatures can be estimated. 
D)  precise positions and relative motions of stars in the Galaxy, from which galactic structure and overall rotation can be determined.

Question 18

Measurements indicate that a certain star has a very high intrinsic brightness (100,000 times as bright as the Sun)and yet is relatively cool (3500 K).How can this be?

Accepted Answer

A)  The star must be quite small. 
B)  The star must be very large. 
C)  There must be an error in observation because no star can have these properties. 
D)  The star must be in the upper part of the main sequence. 
A)  The star must be quite small. 
B)  The star must be very large. 
C)  There must be an error in observation because no star can have these properties. 
D)  The star must be in the upper part of the main sequence.

Question 19

The star ɛ Canis Majoris has an absolute magnitude of -4.1 and a spectral luminosity class of B2 V.The star ϒ Crucis has a spectral class of M4 and the same absolute magnitude as ɛ Canis Majoris.Using Figure 10-10 of Comins,Discovering the Essential Universe,6th ed.,the spectral luminosity class ofϒ Crucis is probably:

Accepted Answer

A)  M-type white dwarf. 
B)  M4 III. 
C)  M4 I. 
D)  M4 V. 
A)  M-type white dwarf. 
B)  M4 III. 
C)  M4 I. 
D)  M4 V.

Question 20

What is the difference between an optical double star and a visual binary star?

Accepted Answer

A)  An optical double is an illusion-the stars are at vast distances from each other and are not actually orbiting each other-whereas in a visual binary, the stars are actually orbiting each other. 
B)  There is no difference-they are two names for the same thing. 
C)  The stars in an optical double star are actually orbiting each other, whereas a visual binary is an illusion-the stars are at vast distances from each other and are not actually orbiting each other. 
D)  Optical double stars can be seen as separate stars only through a telescope, whereas visual binaries can be seen with the unaided eye (e.g., the star Mizar in the Big Dipper's handle). 
A)  An optical double is an illusion-the stars are at vast distances from each other and are not actually orbiting each other-whereas in a visual binary, the stars are actually orbiting each other. 
B)  There is no difference-they are two names for the same thing. 
C)  The stars in an optical double star are actually orbiting each other, whereas a visual binary is an illusion-the stars are at vast distances from each other and are not actually orbiting each other. 
D)  Optical double stars can be seen as separate stars only through a telescope, whereas visual binaries can be seen with the unaided eye (e.g., the star Mizar in the Big Dipper's handle).

If you compare two stars,the one with the _____ must have the greater luminosity.

The star Alphard has an apparent magnitude of 2.0,and the star Megrez has an apparent magnitude of 3.3.The only thing that can be said with certainty about Alphard is that it is _____ than Megrez.

What is parallax?

Which atom or ion produces strong absorption lines in the spectra of stars with relatively cool surface temperatures?

Using the Hertzsprung-Russell diagram and the mass-luminosity relationship for main-sequence stars (Figure 10-14 of Comins,Discovering the Essential Universe,6th ed.),determine which type of main-sequence stars would have the highest mass.

The difference in the brightness of a star as seen through two different colored filters,for example,blue and yellow,is directly related to which stellar property?

Two stars in our sky have the same apparent brightness.If neither of them is hidden behind gas or dust clouds,then we know that they:

The first accurate measurement of stellar parallax was made in:

How are white dwarfs treated in the luminosity class definitions?

A star of apparent magnitude +2.1 appears _____ than a star of apparent magnitude -1.2.

Star A has luminosity LA = 100 L⊙ and it is 1000 pc away.Star B has the same luminosity as the Sun,L⊙,and it is 100 pc away.What can you say about the brightnesses of these two stars?

A particular star appears approximately equally bright when viewed through a blue filter and through a yellow filter.What is the approximate surface temperature of this star? (See Figure 10-4,Comins,Discovering the Essential Universe,6th ed.)

Which is NOT needed to determine individual masses in a binary star system?

Two stars in a binary system orbit around a common point that is:

A star that is 100 pc distant from Earth has an apparent magnitude of m +2.5.According to the equation in Discovery 10-2 in Comins,Discovering the Essential Universe,6th ed.,what is its absolute magnitude?

What proportion of visible stars in our nighttime sky are members of multiple-star systems,such as binary stars?

The technique called photometry in stellar astronomy is the measurement of the:

Measurements indicate that a certain star has a very high intrinsic brightness (100,000 times as bright as the Sun)and yet is relatively cool (3500 K).How can this be?

What is the difference between an optical double star and a visual binary star?

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

The Lives of the Stars From Birth Through Middle Age

The Deaths and Remnants of Stars

The Galaxies

Cosmology

Astrobiology

Filters

Exam 10: Characterizing Stars

If you compare two stars,the one with the _____ must have the greater luminosity.

The star Alphard has an apparent magnitude of 2.0,and the star Megrez has an apparent magnitude of 3.3.The only thing that can be said with certainty about Alphard is that it is _____ than Megrez.

What is parallax?

Which atom or ion produces strong absorption lines in the spectra of stars with relatively cool surface temperatures?

Using the Hertzsprung-Russell diagram and the mass-luminosity relationship for main-sequence stars (Figure 10-14 of Comins,Discovering the Essential Universe,6th ed.),determine which type of main-sequence stars would have the highest mass.

The difference in the brightness of a star as seen through two different colored filters,for example,blue and yellow,is directly related to which stellar property?

Two stars in our sky have the same apparent brightness.If neither of them is hidden behind gas or dust clouds,then we know that they:

The first accurate measurement of stellar parallax was made in:

How are white dwarfs treated in the luminosity class definitions?

A star of apparent magnitude +2.1 appears _____ than a star of apparent magnitude -1.2.

Star A has luminosity LA = 100 L⊙ and it is 1000 pc away.Star B has the same luminosity as the Sun,L⊙,and it is 100 pc away.What can you say about the brightnesses of these two stars?

A particular star appears approximately equally bright when viewed through a blue filter and through a yellow filter.What is the approximate surface temperature of this star? (See Figure 10-4,Comins,Discovering the Essential Universe,6th ed.)

Which is NOT needed to determine individual masses in a binary star system?

Two stars in a binary system orbit around a common point that is:

A star that is 100 pc distant from Earth has an apparent magnitude of m +2.5.According to the equation in Discovery 10-2 in Comins,Discovering the Essential Universe,6th ed.,what is its absolute magnitude?

What proportion of visible stars in our nighttime sky are members of multiple-star systems,such as binary stars?

The technique called photometry in stellar astronomy is the measurement of the:

Measurements indicate that a certain star has a very high intrinsic brightness (100,000 times as bright as the Sun)and yet is relatively cool (3500 K).How can this be?

What is the difference between an optical double star and a visual binary star?

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

The Lives of the Stars From Birth Through Middle Age

The Deaths and Remnants of Stars

The Galaxies

Cosmology

Astrobiology

Filters