Question 1

In 2013,the European Space Agency launched the Gaia mission,which will measure parallax angles down to 10-⁵ arcseconds.What distance does this correspond to?

Accepted Answer

A)  10-⁵ pc 
B)  10⁵ light-years 
C)  100 kpc 
D)  200 kpc 
A)  10-⁵ pc 
B)  10⁵ light-years 
C)  100 kpc 
D)  200 kpc

Question 2

Spectral classification of a star into the lettered categories,O,B,A,F,G,K,and M is carried out by:

Accepted Answer

A)  finding the wavelength of peak emission in the continuum spectrum of the star. 
B)  determining the relative mass of the star by the study of binary star motions, in order to place it into its proper mass classification. 
C)  determining the total energy emitted at all wavelengths by the star, taking account of the full spread of wavelengths and their distances, in order to place the star into its luminosity class. 
D)  examining the relative depths of absorption lines from various neutral and ionized atoms in a stellar spectrum. 
A)  finding the wavelength of peak emission in the continuum spectrum of the star. 
B)  determining the relative mass of the star by the study of binary star motions, in order to place it into its proper mass classification. 
C)  determining the total energy emitted at all wavelengths by the star, taking account of the full spread of wavelengths and their distances, in order to place the star into its luminosity class. 
D)  examining the relative depths of absorption lines from various neutral and ionized atoms in a stellar spectrum.

Question 3

What will be the intrinsic brightness or luminosity of a white dwarf star that has the same temperature as the Sun? (See Figure 10-7,Comins,Discovering the Universe,6th ed.)

Accepted Answer

A)  4 times the Sun's luminosity 
B)  Because it has the same surface temperature, the white dwarf will have the same brightness. 
C)  10-² of the Sun's luminosity 
D)  10-⁴ of the Sun's luminosity 
A)  4 times the Sun's luminosity 
B)  Because it has the same surface temperature, the white dwarf will have the same brightness. 
C)  10-² of the Sun's luminosity 
D)  10-⁴ of the Sun's luminosity

Question 4

Very hot stars have weak hydrogen spectral lines.Why is this?

Accepted Answer

A)  These stars contain very little hydrogen. 
B)  The hydrogen in the atmospheres of these stars is combined into molecules, and these have different spectra. 
C)  The electrons in the hydrogen atoms in these stars are all in their lowest energy levels, and they cannot radiate from these levels. 
D)  The hydrogen atoms in these stars are mostly ionized and hence cannot radiate. 
A)  These stars contain very little hydrogen. 
B)  The hydrogen in the atmospheres of these stars is combined into molecules, and these have different spectra. 
C)  The electrons in the hydrogen atoms in these stars are all in their lowest energy levels, and they cannot radiate from these levels. 
D)  The hydrogen atoms in these stars are mostly ionized and hence cannot radiate.

Question 5

What is the relationship between stellar parallax (p)measured in seconds of arc and distance (d)measured in parsecs?

Accepted Answer

A)  d = 1/p² 
B)  d = 1/p 
C)  d = p 
D)  d = p² 
A)  d = 1/p² 
B)  d = 1/p 
C)  d = p 
D)  d = p²

Question 6

As you drive along a road,trees in the middle distance seem to shift in position relative to faraway hills.What name is given to this phenomenon?

Accepted Answer

A)  parallax 
B)  perspective 
C)  Doppler effect 
D)  inverse-square law 
A)  parallax 
B)  perspective 
C)  Doppler effect 
D)  inverse-square law

Question 7

Which is NOT a true binary system?

Accepted Answer

A)  optical double 
B)  visual binary 
C)  spectroscopic binary 
D)  eclipsing binary 
A)  optical double 
B)  visual binary 
C)  spectroscopic binary 
D)  eclipsing binary

Question 8

When observed through a set of photometric filters,a distant star is seen to be brightest through the ultraviolet filter,less bright through the blue filter,and faintest through the yellow filter.What conclusion can be drawn from this information,assuming no absorption of light between the star and Earth?

Accepted Answer

A)  The question gives insufficient information to draw a conclusion about a star's surface temperature. 
B)  The star has an intermediate temperature close to that of the Sun. 
C)  The star has a very high surface temperature. 
D)  The star has a very low surface temperature. 
A)  The question gives insufficient information to draw a conclusion about a star's surface temperature. 
B)  The star has an intermediate temperature close to that of the Sun. 
C)  The star has a very high surface temperature. 
D)  The star has a very low surface temperature.

Question 9

Two stars have the same luminosity (or absolute magnitude).One star is spectral class F and the other is spectral class K.From this information,we know that the:

Accepted Answer

A)  K-type star is larger than the B-type star. 
B)  B-type star is larger than the K-type star. 
C)  B-type star is hotter but can be larger, smaller, or the same size as the K-type star. 
D)  K-type star is hotter but can be larger, smaller, or the same size as the B-type star. 
A)  K-type star is larger than the B-type star. 
B)  B-type star is larger than the K-type star. 
C)  B-type star is hotter but can be larger, smaller, or the same size as the K-type star. 
D)  K-type star is hotter but can be larger, smaller, or the same size as the B-type star.

Question 10

If the Hipparcos satellite measures the parallax motion of a star against the background stars and concludes that the star has a parallax of 0.004 arcsec,how far is the star from Earth?

Accepted Answer

A)  25 pc, or 81.5 ly 
B)  250 pc, or 815 ly 
C)  400 pc, or 1300 ly 
D)  0.004 pc, or 0.013 ly 
A)  25 pc, or 81.5 ly 
B)  250 pc, or 815 ly 
C)  400 pc, or 1300 ly 
D)  0.004 pc, or 0.013 ly

Question 11

How bright (in absolute magnitude)are the intrinsically brightest stars in the universe?

Accepted Answer

A)  +17 
B)  +1 
C)  0 
D)  -10 
A)  +17 
B)  +1 
C)  0 
D)  -10

Question 12

The reason a doubly ionized helium gas,He III,will not produce absorption lines in a stellar spectrum is that:

Accepted Answer

A)  a doubly ionized helium atom is simply a helium nucleus stripped of all its electrons, so it cannot absorb visible photons. 
B)  the gas temperature on any star is always so high that electrons are excited beyond energy levels in the atoms from which visible photons can be absorbed. 
C)  doubly ionized helium is meaningless because neutral helium contains only one electron. 
D)  the gas temperature on star surfaces can never be hot enough to excite electrons in this atom to levels from which they will absorb visible photons. 
A)  a doubly ionized helium atom is simply a helium nucleus stripped of all its electrons, so it cannot absorb visible photons. 
B)  the gas temperature on any star is always so high that electrons are excited beyond energy levels in the atoms from which visible photons can be absorbed. 
C)  doubly ionized helium is meaningless because neutral helium contains only one electron. 
D)  the gas temperature on star surfaces can never be hot enough to excite electrons in this atom to levels from which they will absorb visible photons.

Question 13

Three stars have the following apparent (m)and absolute (M)magnitudes: Star A: M = 1.8 m = 3.8
Star B: M = 2.5 m = 9.5
Star C: M = 7.6 m = 15.1
Which star is farthest away?

Accepted Answer

A)  Star A 
B)  Star B 
C)  Star C 
D)  cannot be determined from these data 
A)  Star A 
B)  Star B 
C)  Star C 
D)  cannot be determined from these data

Question 14

Which observation would NOT be an indication of a binary star system?

Accepted Answer

A)  The "star" appears to move in a straight line against a background field of stars. 
B)  A "star" appears to become periodically dimmer and then brighter for a few hours at a time. 
C)  A "star" image periodically separates into two distinct images and then blends again. 
D)  The "star" appears to wiggle in its path across Earth's sky against the background stars. 
A)  The "star" appears to move in a straight line against a background field of stars. 
B)  A "star" appears to become periodically dimmer and then brighter for a few hours at a time. 
C)  A "star" image periodically separates into two distinct images and then blends again. 
D)  The "star" appears to wiggle in its path across Earth's sky against the background stars.

Question 15

What is a dwarf star?

Accepted Answer

A)  a main-sequence star 
B)  a large, planetary object, such as Jupiter 
C)  a star of about the same size (diameter) as Earth 
D)  a star that is significantly smaller than a giant or supergiant star 
A)  a main-sequence star 
B)  a large, planetary object, such as Jupiter 
C)  a star of about the same size (diameter) as Earth 
D)  a star that is significantly smaller than a giant or supergiant star

Question 16

Two stars,P and Q,can be seen in the same region of Earth's sky with the same apparent magnitude,but star Q is twice as far away as star P.What is the ratio of the luminosities of these stars (star P/star Q)?

Accepted Answer

A)  4 
B)  2 
C)  1/4 
D)  1/2 
A)  4 
B)  2 
C)  1/4 
D)  1/2

Question 17

The star α Centauri C and the star Groombridge 34 B have the same apparent magnitude,but α Centauri C is 1.3 pc away from Earth and Groombridge 34 B is 3.5 pc away.What is the luminosity of Groombridge 34 B compared with α Centauri C? (See Figure 10-3,Comins,Discovering the Essential Universe,6th ed.)

Accepted Answer

A)  2.7 times brighter 
B)  7.2 times fainter 
C)  2.7 times fainter 
D)  7.2 times brighter 
A)  2.7 times brighter 
B)  7.2 times fainter 
C)  2.7 times fainter 
D)  7.2 times brighter

Question 18

A star is 80 pc from the Sun.Its apparent motion against the background sky as a result of Earth's motion through 1 AU; that is,its stellar parallax,is:

Accepted Answer

A)  0.0125 arcsecond. 
B)  0.0125 arcminute. 
C)  0.0125 radian, or 0.72°. 
D)  80 arcseconds. 
A)  0.0125 arcsecond. 
B)  0.0125 arcminute. 
C)  0.0125 radian, or 0.72°. 
D)  80 arcseconds.

Question 19

Which stellar classification is for a star hotter than an F5 star?

Accepted Answer

A)  F9 
B)  K2 
C)  M0 
D)  B2 
A)  F9 
B)  K2 
C)  M0 
D)  B2

Question 20

Stellar parallax is the:

Accepted Answer

A)  inferred change in the distance to a star as its light is dimmed by passing through an interstellar cloud. 
B)  apparent shift seen in the position of a nearby star against more distant stars as Earth orbits the Sun. 
C)  difference between the apparent and absolute magnitudes of a star. 
D)  circular or elliptical motion of a star in a binary system as the two stars orbit each other. 
A)  inferred change in the distance to a star as its light is dimmed by passing through an interstellar cloud. 
B)  apparent shift seen in the position of a nearby star against more distant stars as Earth orbits the Sun. 
C)  difference between the apparent and absolute magnitudes of a star. 
D)  circular or elliptical motion of a star in a binary system as the two stars orbit each other.

In 2013,the European Space Agency launched the Gaia mission,which will measure parallax angles down to 10-⁵ arcseconds.What distance does this correspond to?

Spectral classification of a star into the lettered categories,O,B,A,F,G,K,and M is carried out by:

What will be the intrinsic brightness or luminosity of a white dwarf star that has the same temperature as the Sun? (See Figure 10-7,Comins,Discovering the Universe,6th ed.)

Very hot stars have weak hydrogen spectral lines.Why is this?

What is the relationship between stellar parallax (p)measured in seconds of arc and distance (d)measured in parsecs?

As you drive along a road,trees in the middle distance seem to shift in position relative to faraway hills.What name is given to this phenomenon?

Which is NOT a true binary system?

Two stars have the same luminosity (or absolute magnitude).One star is spectral class F and the other is spectral class K.From this information,we know that the:

If the Hipparcos satellite measures the parallax motion of a star against the background stars and concludes that the star has a parallax of 0.004 arcsec,how far is the star from Earth?

How bright (in absolute magnitude)are the intrinsically brightest stars in the universe?

The reason a doubly ionized helium gas,He III,will not produce absorption lines in a stellar spectrum is that:

Three stars have the following apparent (m)and absolute (M)magnitudes: Star A: M = 1.8 m = 3.8 Star B: M = 2.5 m = 9.5 Star C: M = 7.6 m = 15.1 Which star is farthest away?

Which observation would NOT be an indication of a binary star system?

What is a dwarf star?

Two stars,P and Q,can be seen in the same region of Earth's sky with the same apparent magnitude,but star Q is twice as far away as star P.What is the ratio of the luminosities of these stars (star P/star Q)?

A star is 80 pc from the Sun.Its apparent motion against the background sky as a result of Earth's motion through 1 AU; that is,its stellar parallax,is:

Which stellar classification is for a star hotter than an F5 star?

Stellar parallax is the:

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

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Exam 10: Characterizing Stars

In 2013,the European Space Agency launched the Gaia mission,which will measure parallax angles down to 10-⁵ arcseconds.What distance does this correspond to?

Spectral classification of a star into the lettered categories,O,B,A,F,G,K,and M is carried out by:

What will be the intrinsic brightness or luminosity of a white dwarf star that has the same temperature as the Sun? (See Figure 10-7,Comins,Discovering the Universe,6th ed.)

Very hot stars have weak hydrogen spectral lines.Why is this?

What is the relationship between stellar parallax (p)measured in seconds of arc and distance (d)measured in parsecs?

As you drive along a road,trees in the middle distance seem to shift in position relative to faraway hills.What name is given to this phenomenon?

Which is NOT a true binary system?

Two stars have the same luminosity (or absolute magnitude).One star is spectral class F and the other is spectral class K.From this information,we know that the:

If the Hipparcos satellite measures the parallax motion of a star against the background stars and concludes that the star has a parallax of 0.004 arcsec,how far is the star from Earth?

How bright (in absolute magnitude)are the intrinsically brightest stars in the universe?

The reason a doubly ionized helium gas,He III,will not produce absorption lines in a stellar spectrum is that:

Three stars have the following apparent (m)and absolute (M)magnitudes: Star A: M = 1.8 m = 3.8 Star B: M = 2.5 m = 9.5 Star C: M = 7.6 m = 15.1 Which star is farthest away?

Which observation would NOT be an indication of a binary star system?

What is a dwarf star?

Two stars,P and Q,can be seen in the same region of Earth's sky with the same apparent magnitude,but star Q is twice as far away as star P.What is the ratio of the luminosities of these stars (star P/star Q)?

A star is 80 pc from the Sun.Its apparent motion against the background sky as a result of Earth's motion through 1 AU; that is,its stellar parallax,is:

Which stellar classification is for a star hotter than an F5 star?

Stellar parallax is the:

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