Question 1

A star's position in the H-R diagram is determined by its

Accepted Answer

A)  temperature and size. 
B)  temperature and distance. 
C)  brightness and size. 
D)  mass and distance. 
E)  brightness and distance. 
A)  temperature and size. 
B)  temperature and distance. 
C)  brightness and size. 
D)  mass and distance. 
E)  brightness and distance.

Question 2

The sequence of stellar spectral types is shown in the figure below.Explain why the hottest star (O5) has so little emission in the visible portion of the spectrum (450-700 nm), spectral types F-K show the most emission in the visible band, and still cooler stars (M type) once again show very little in the visible band.

Accepted Answer

O stars are very hot blackbodies (40,000

Question 3

The figure below is an H-R diagram of 4 million stars from the Gaia satellite, with the main sequence labeled.What are the names and properties of the stars not found on the main sequence?

Accepted Answer

Above the main sequence lie the giant st

Question 4

Which stars are the most common?

Accepted Answer

A)  stars with a mass and a radius larger than the Sun's 
B)  stars with a smaller mass and radius than the Sun's 
C)  stars with a mass larger than the Sun's and a radius smaller than the Sun's 
D)  stars with a mass smaller than the Sun's and a radius larger than the Sun's 
E)  All of these are equally common. 
A)  stars with a mass and a radius larger than the Sun's 
B)  stars with a smaller mass and radius than the Sun's 
C)  stars with a mass larger than the Sun's and a radius smaller than the Sun's 
D)  stars with a mass smaller than the Sun's and a radius larger than the Sun's 
E)  All of these are equally common.

Question 5

What advantage do you gain by having two eyes that are separated on your face, rather than being very close together?

Accepted Answer

A)  better collecting area, which allows you to see dimmer objects 
B)  double vision, which allows you to see multiple objects at once 
C)  color vision, which allows you to determine temperatures 
D)  stereoscopic vision, which allows you to determine distances 
E)  better magnification, which allows you to see smaller objects 
A)  better collecting area, which allows you to see dimmer objects 
B)  double vision, which allows you to see multiple objects at once 
C)  color vision, which allows you to determine temperatures 
D)  stereoscopic vision, which allows you to determine distances 
E)  better magnification, which allows you to see smaller objects

Question 6

On a typical H-R diagram, where are the stars with the largest radii located?

Accepted Answer

A)  in the upper left corner 
B)  in the upper right corner 
C)  in the center 
D)  in the lower left corner 
E)  in the lower right corner 
A)  in the upper left corner 
B)  in the upper right corner 
C)  in the center 
D)  in the lower left corner 
E)  in the lower right corner

Question 7

Star A is a red star.Star B is a blue star.Which star is hotter?

Accepted Answer

A)  Star A is hotter. 
B)  Star B is hotter. 
C)  They are the same temperature. 
D)  We also need to know the luminosities of the stars to determine their temperatures. 
E)  Color is not related to temperature at all. 
A)  Star A is hotter. 
B)  Star B is hotter. 
C)  They are the same temperature. 
D)  We also need to know the luminosities of the stars to determine their temperatures. 
E)  Color is not related to temperature at all.

Question 8

Star E is the same temperature as star F, but star E is four times as luminous as star F.How do the radii of the stars compare?

Accepted Answer

A)  The radius of star E is twice that of star F. 
B)  The radius of star E is four times that of star F. 
C)  The radius of star F is twice that of star E. 
D)  The radius of star F is four times that of star E. 
E)  The radii are the same length. 
A)  The radius of star E is twice that of star F. 
B)  The radius of star E is four times that of star F. 
C)  The radius of star F is twice that of star E. 
D)  The radius of star F is four times that of star E. 
E)  The radii are the same length.

Question 9

How does the size and distance of a habitable zone depend on the spectral type of the star?

Accepted Answer

Habitable zones (distances from the star

Question 10

The brightest stars in the sky also tend to be

Accepted Answer

A)  the oldest stars. 
B)  the reddest stars in the sky. 
C)  very near to us (within 5 parsecs). 
D)  very luminous. 
E)  the smallest stars. 
A)  the oldest stars. 
B)  the reddest stars in the sky. 
C)  very near to us (within 5 parsecs). 
D)  very luminous. 
E)  the smallest stars.

Question 11

The figure below shows an H-R diagram, with five stars labeled A through E.Which of the main-sequence stars has the smallest mass?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
E)  E 
A)  A 
B)  B 
C)  C 
D)  D 
E)  E

Question 12

If star A has a temperature that is twice as hot as the Sun, but it has the same luminosity as the Sun, the diameter of star A must be ________ times the diameter of the Sun.

Accepted Answer

A)  16 
B)  4 
C)  2 
D)  1/2 
E)  1/4 
A)  16 
B)  4 
C)  2 
D)  1/2 
E)  1/4

Question 13

A star in the lower-left corner of the H-R diagram must be

Accepted Answer

A)  large and hot. 
B)  large and cold. 
C)  small and cold. 
D)  small and hot. 
E)  none of these 
A)  large and hot. 
B)  large and cold. 
C)  small and cold. 
D)  small and hot. 
E)  none of these

Question 14

Explain how we can use spectroscopic parallax to determine the distance to a star farther away than a few hundred light-years.

Accepted Answer

First,we can determine the temperature o

Question 15

Two stars with similar temperatures but different sizes will have

Accepted Answer

A)  similar spectral types but different luminosities. 
B)  similar luminosities but different brightnesses. 
C)  similar brightnesses but different distances. 
D)  similar distances but different masses. 
E)  similar masses but different spectral types. 
A)  similar spectral types but different luminosities. 
B)  similar luminosities but different brightnesses. 
C)  similar brightnesses but different distances. 
D)  similar distances but different masses. 
E)  similar masses but different spectral types.

Question 16

Star C is a red star.Star D is a blue star.Which has a larger radius?

Accepted Answer

A)  Star C has a larger radius. 
B)  Star D has a larger radius. 
C)  Stars C and D have the same radius. 
D)  We also need to know the luminosities of the stars to determine their radii. 
E)  We also need to know the age of the stars to determine their radii. 
A)  Star C has a larger radius. 
B)  Star D has a larger radius. 
C)  Stars C and D have the same radius. 
D)  We also need to know the luminosities of the stars to determine their radii. 
E)  We also need to know the age of the stars to determine their radii.

Question 17

How many arcseconds are there in 1 degree?

Accepted Answer

A)  60 
B)  360 
C)  3,600 
D)  6,000 
E)  36,000 
A)  60 
B)  360 
C)  3,600 
D)  6,000 
E)  36,000

Question 18

Explain how astronomers can use the blue and visible filters to determine the temperatures of stars.

Accepted Answer

Astronomers compare the relati

Question 19

What type of spectrum do most stars produce?

Accepted Answer

A)  an absorption spectrum on top of a blackbody spectrum 
B)  an emission spectrum on top of a blackbody spectrum 
C)  an absorption spectrum on top of an emission spectrum 
D)  a pure emission spectrum 
E)  a pure blackbody spectrum 
A)  an absorption spectrum on top of a blackbody spectrum 
B)  an emission spectrum on top of a blackbody spectrum 
C)  an absorption spectrum on top of an emission spectrum 
D)  a pure emission spectrum 
E)  a pure blackbody spectrum

Question 20

Imagine you are observing a nearby star.You know that it is a main-sequence star but don't know anything else about it.If you had access to any telescope equipment you wanted, explain how you would determine this star's temperature, luminosity, distance, and radius.

Accepted Answer

You could measure the temperature either

Exam 13: Taking the Measure of Stars

A star's position in the H-R diagram is determined by its

The figure below is an H-R diagram of 4 million stars from the Gaia satellite, with the main sequence labeled.What are the names and properties of the stars not found on the main sequence?

Which stars are the most common?

What advantage do you gain by having two eyes that are separated on your face, rather than being very close together?

On a typical H-R diagram, where are the stars with the largest radii located?

Star A is a red star.Star B is a blue star.Which star is hotter?

Star E is the same temperature as star F, but star E is four times as luminous as star F.How do the radii of the stars compare?

How does the size and distance of a habitable zone depend on the spectral type of the star?

The brightest stars in the sky also tend to be

The figure below shows an H-R diagram, with five stars labeled A through E.Which of the main-sequence stars has the smallest mass?

If star A has a temperature that is twice as hot as the Sun, but it has the same luminosity as the Sun, the diameter of star A must be ________ times the diameter of the Sun.

A star in the lower-left corner of the H-R diagram must be

Explain how we can use spectroscopic parallax to determine the distance to a star farther away than a few hundred light-years.

Two stars with similar temperatures but different sizes will have

Star C is a red star.Star D is a blue star.Which has a larger radius?

How many arcseconds are there in 1 degree?

Explain how astronomers can use the blue and visible filters to determine the temperatures of stars.

What type of spectrum do most stars produce?

Imagine you are observing a nearby star.You know that it is a main-sequence star but don't know anything else about it.If you had access to any telescope equipment you wanted, explain how you would determine this star's temperature, luminosity, distance, and radius.

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Formation of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Planetary Moons and Rings

Dwarf Planets and Small Solar System Bodies

Our Starthe Sun

The Interstellar Medium and Star Formation

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

Galaxies

The Milky Waya Normal Spiral Galaxy

The Expanding Universe

Cosmology

Large-Scale Structure in the Universe

Life

Filters