Question 1

A star moving toward the Sun will show:

Accepted Answer

A)  a shift in the spectral lines toward the blue end (as compared to the laboratory positions of these lines) 
B)  a significant increase in its apparent brightness (magnitude) 
C)  more and more helium lines as it approaches us 
D)  a shift in the spectral lines toward the red end (as compared to the laboratory positions of these lines) 
E)  no change that can be measured with our present-day instruments 
A)  a shift in the spectral lines toward the blue end (as compared to the laboratory positions of these lines) 
B)  a significant increase in its apparent brightness (magnitude) 
C)  more and more helium lines as it approaches us 
D)  a shift in the spectral lines toward the red end (as compared to the laboratory positions of these lines) 
E)  no change that can be measured with our present-day instruments

Question 2

Astronomers arrange the stars into groups called spectral classes (or types) according to the kinds of lines they find in their spectra. These spectral classes are arranged in order of:

Accepted Answer

A)  decreasing surface temperature 
B)  increasing mass 
C)  increasing amount of hydrogen 
D)  decreasing distance from us 
E)  you can't fool me, there is no order to the spectral types (that's why the letters are not in alphabetical order) 
A)  decreasing surface temperature 
B)  increasing mass 
C)  increasing amount of hydrogen 
D)  decreasing distance from us 
E)  you can't fool me, there is no order to the spectral types (that's why the letters are not in alphabetical order)

Question 3

Which of the following types of star is the coolest (has the lowest surface temperature)?

Accepted Answer

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

Question 4

Some objects in space just don't have what it takes to be a star (just like many hopefuls in Hollywood don't.) Which of the following is a "failed star", an object with too little mass to qualify as a star?

Accepted Answer

A)  a brown dwarf 
B)  an M type dwarf 
C)  an O-type star 
D)  the Sun 
E)  any star with high proper motion 
A)  a brown dwarf 
B)  an M type dwarf 
C)  an O-type star 
D)  the Sun 
E)  any star with high proper motion

Question 5

An exhausted-looking astronomer comes off the mountain where her observatory is located and tells you she has been doing photometry all night. What has she been up to?

Accepted Answer

A)  taking photos through bedroom windows in the valley below 
B)  measuring the positions of stars on photographic plates taken over many years 
C)  putting the light of stars through a spectrograph to measure what elements are present 
D)  measuring the brightness of different stars 
E)  counting the number of stars in different star clusters (groups) 
A)  taking photos through bedroom windows in the valley below 
B)  measuring the positions of stars on photographic plates taken over many years 
C)  putting the light of stars through a spectrograph to measure what elements are present 
D)  measuring the brightness of different stars 
E)  counting the number of stars in different star clusters (groups)

Question 6

If hydrogen is the most common element in the universe, why do we not see the lines of hydrogen in the spectra of the hottest stars?

Accepted Answer

A)  in the hottest stars, hydrogen nuclei are forced to break apart into smaller nuclei 
B)  in the hottest stars, all hydrogen in the star has quickly fused into helium 
C)  in the hottest stars, hydrogen can quickly combine with oxygen to make H2O, whose spectrum consists of completely different lines 
D)  in the hottest stars, the hydrogen atoms experience a huge Doppler shift, which moves the lines in the spectrum to a completely unrecognizable place 
E)  in the hottest stars, hydrogen atoms are ionized, and so there are no electrons to produce lines in the spectrum 
A)  in the hottest stars, hydrogen nuclei are forced to break apart into smaller nuclei 
B)  in the hottest stars, all hydrogen in the star has quickly fused into helium 
C)  in the hottest stars, hydrogen can quickly combine with oxygen to make H2O, whose spectrum consists of completely different lines 
D)  in the hottest stars, the hydrogen atoms experience a huge Doppler shift, which moves the lines in the spectrum to a completely unrecognizable place 
E)  in the hottest stars, hydrogen atoms are ionized, and so there are no electrons to produce lines in the spectrum

Question 7

At an astronomical conference, an astronomer gives a report on a star that interests astronomers because of hints that it may have a planet around it. In his report the astronomer gives the average speed with which this star is moving away from the Sun. How did the astronomer measure this speed?

Accepted Answer

A)  by seeing how the luminosity of the star has been decreasing as it moves farther and farther away 
B)  by seeing the whole star become much redder than it used to be 
C)  by measuring the diameter of the star (which is easy to do) and noticing that it is getting smaller and smaller 
D)  by looking at the Doppler shift in the lines of the star's spectrum 
E)  the astronomer must be making up stories to impress his colleagues; there is no way to measure the speed with which stars move away or toward us. 
A)  by seeing how the luminosity of the star has been decreasing as it moves farther and farther away 
B)  by seeing the whole star become much redder than it used to be 
C)  by measuring the diameter of the star (which is easy to do) and noticing that it is getting smaller and smaller 
D)  by looking at the Doppler shift in the lines of the star's spectrum 
E)  the astronomer must be making up stories to impress his colleagues; there is no way to measure the speed with which stars move away or toward us.

A star moving toward the Sun will show:

Astronomers arrange the stars into groups called spectral classes (or types) according to the kinds of lines they find in their spectra. These spectral classes are arranged in order of:

Which of the following types of star is the coolest (has the lowest surface temperature)?

Some objects in space just don't have what it takes to be a star (just like many hopefuls in Hollywood don't.) Which of the following is a "failed star", an object with too little mass to qualify as a star?

An exhausted-looking astronomer comes off the mountain where her observatory is located and tells you she has been doing photometry all night. What has she been up to?

If hydrogen is the most common element in the universe, why do we not see the lines of hydrogen in the spectra of the hottest stars?

At an astronomical conference, an astronomer gives a report on a star that interests astronomers because of hints that it may have a planet around it. In his report the astronomer gives the average speed with which this star is moving away from the Sun. How did the astronomer measure this speed?

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

The Stars: a Celestial Census

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 17: Analyzing Starlight

A star moving toward the Sun will show:

Astronomers arrange the stars into groups called spectral classes (or types) according to the kinds of lines they find in their spectra. These spectral classes are arranged in order of:

Which of the following types of star is the coolest (has the lowest surface temperature)?

Some objects in space just don't have what it takes to be a star (just like many hopefuls in Hollywood don't.) Which of the following is a "failed star", an object with too little mass to qualify as a star?

An exhausted-looking astronomer comes off the mountain where her observatory is located and tells you she has been doing photometry all night. What has she been up to?

If hydrogen is the most common element in the universe, why do we not see the lines of hydrogen in the spectra of the hottest stars?

At an astronomical conference, an astronomer gives a report on a star that interests astronomers because of hints that it may have a planet around it. In his report the astronomer gives the average speed with which this star is moving away from the Sun. How did the astronomer measure this speed?

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

The Stars: a Celestial Census

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