Question 1

A star that has an apparent magnitude of 0 (see Figure 10-2,Comins,Discovering the Essential Universe,6th ed.)would:

Accepted Answer

A)  be fainter than Spica (α Virginis), which has an apparent magnitude of +1.0. 
B)  be brighter than Deneb (α Cygni), which has an apparent magnitude of +1.2. 
C)  have infinite brightness since 1/0 = infinity. 
D)  not be emitting any light and therefore could not be seen from Earth. 
A)  be fainter than Spica (α Virginis), which has an apparent magnitude of +1.0. 
B)  be brighter than Deneb (α Cygni), which has an apparent magnitude of +1.2. 
C)  have infinite brightness since 1/0 = infinity. 
D)  not be emitting any light and therefore could not be seen from Earth.

Question 2

By examining a star's spectrum we can determine each of the following EXCEPT ONE.Which is the exception?

Accepted Answer

A)  the star's spectral class 
B)  the star's neutrino flux 
C)  the star's luminosity class 
D)  the star's radial motion 
A)  the star's spectral class 
B)  the star's neutrino flux 
C)  the star's luminosity class 
D)  the star's radial motion

Question 3

The semimajor axis of Pluto's orbit is almost 40 AU.The smallest parallax angle we can measure from orbiting observatories is about 0.001 arcsec.Suppose we use this technique to measure parallax from Pluto's orbit (over the course of half a Pluto "year").What is the maximum distance we could measure?

Accepted Answer

A)  40 pc 
B)  1000 pc 
C)  40,000 pc 
D)  80,000 pc 
A)  40 pc 
B)  1000 pc 
C)  40,000 pc 
D)  80,000 pc

Question 4

A star is at such a distance that its apparent magnitude (m)is 10 magnitudes fainter than its absolute magnitude (M).How far away is it?

Accepted Answer

A)  10 pc 
B)  100 pc 
C)  1000 pc 
D)  10,000 pc 
A)  10 pc 
B)  100 pc 
C)  1000 pc 
D)  10,000 pc

Question 5

It was discovered that stars of the same temperature can include stars of different radii.The response to this finding was to:

Accepted Answer

A)  refine the spectral classification scheme by introducing subheadings 0-9. 
B)  revise the spectral classification to start with O rather than A. 
C)  define the luminosity classes. 
D)  invent the H-R diagram. 
A)  refine the spectral classification scheme by introducing subheadings 0-9. 
B)  revise the spectral classification to start with O rather than A. 
C)  define the luminosity classes. 
D)  invent the H-R diagram.

Question 6

A star of apparent magnitude -2 appears _____ than a star of apparent magnitude -3.

Accepted Answer

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

Question 7

A simple relationship exists between mass and luminosity for:

Accepted Answer

A)  all stars. 
B)  main-sequence stars only. 
C)  giant stars and main-sequence stars. 
D)  main-sequence stars and brown dwarfs. 
A)  all stars. 
B)  main-sequence stars only. 
C)  giant stars and main-sequence stars. 
D)  main-sequence stars and brown dwarfs.

Question 8

The equation for the luminosity of a star in terms of its surface temperature is L = (surface area)σT⁴,where σ is the Stefan-Boltzmann constant.This suggests that,when a plot is made of luminosities versus temperature:

Accepted Answer

A)  stars of the same temperature but different radii should occupy different points on the plot. 
B)  all stars should plot along the line. 
C)  larger stars must have higher temperatures. 
D)  smaller stars must have higher temperatures. 
A)  stars of the same temperature but different radii should occupy different points on the plot. 
B)  all stars should plot along the line. 
C)  larger stars must have higher temperatures. 
D)  smaller stars must have higher temperatures.

Question 9

The radial velocity curve of a star in a binary star system is a plot against time of the:

Accepted Answer

A)  speed of the star in a direction perpendicular to the line of sight to the star. 
B)  position of the star in celestial coordinates. 
C)  variation of Doppler shift of the star's spectral lines and hence of its speed toward or away from us. 
D)  temperature of the star as determined from the movement of the peak wavelength of its spectrum. 
A)  speed of the star in a direction perpendicular to the line of sight to the star. 
B)  position of the star in celestial coordinates. 
C)  variation of Doppler shift of the star's spectral lines and hence of its speed toward or away from us. 
D)  temperature of the star as determined from the movement of the peak wavelength of its spectrum.

Question 10

How far away is the nearest star beyond the Sun,in parsecs?

Accepted Answer

A)  between 1 and 2 pc 
B)  about 12 pc 
C)  about 4 pc 
D)  between 1/2 and 1 pc 
A)  between 1 and 2 pc 
B)  about 12 pc 
C)  about 4 pc 
D)  between 1/2 and 1 pc

Question 11

A particular star has an angle of parallax of 0.1 arcsec.What is the distance to this star?

Accepted Answer

A)  about 10 ly 
B)  about 33 ly 
C)  about 0.1 ly 
D)  about 3.3 ly 
A)  about 10 ly 
B)  about 33 ly 
C)  about 0.1 ly 
D)  about 3.3 ly

Question 12

A red filter passes light at the long-wavelength end of the visible spectrum as shown,for example,in Figure 10-4 in Comins,Discovering the Essential Universe,6th ed.Star 1 and star 2 are viewed through identical red filters,and star 1 appears brighter than star 2 through the filter.What can be determined from this information?

Accepted Answer

A)  Star 1 is hotter than star 2. 
B)  Star 2 is hotter than star 1. 
C)  Star 1 is more luminous than star 2. 
D)  Nothing can be concluded from this fact alone. 
A)  Star 1 is hotter than star 2. 
B)  Star 2 is hotter than star 1. 
C)  Star 1 is more luminous than star 2. 
D)  Nothing can be concluded from this fact alone.

Question 13

A particular star appears fainter seen through a blue filter than seen through a yellow filter.Which surface temperature is possible for this star? (See Figure 10-4,Comins,Discovering the Essential Universe,6th ed.)

Accepted Answer

A)  12,500 K 
B)  38,000 K 
C)  8800 K 
D)  3800 K 
A)  12,500 K 
B)  38,000 K 
C)  8800 K 
D)  3800 K

Question 14

Suppose that two identical stars (they have the same total light output)are located so that star A is at a distance of 5 pc and star B is at a distance of 25 pc from Earth.How will star B appear,compared with star A?

Accepted Answer

A)  Star B will be 1/5 as bright as star A. 
B)  Star B will be 1/25 as bright as star A. 
C)  Star B will be 1/2.2 as bright as star A. 
D)  Star B will be 1/20 as bright as star A. 
A)  Star B will be 1/5 as bright as star A. 
B)  Star B will be 1/25 as bright as star A. 
C)  Star B will be 1/2.2 as bright as star A. 
D)  Star B will be 1/20 as bright as star A.

Question 15

What is the ONLY way to measure the mass of a star accurately?

Accepted Answer

A)  Measure its distance using trigonometric parallax and its brightness using photometry. 
B)  It is not possible to measure the mass of a star. 
C)  Measure its spectral type and luminosity class, then use the H-R diagram. 
D)  Measure its gravitational effect on another object. 
A)  Measure its distance using trigonometric parallax and its brightness using photometry. 
B)  It is not possible to measure the mass of a star. 
C)  Measure its spectral type and luminosity class, then use the H-R diagram. 
D)  Measure its gravitational effect on another object.

Question 16

A particular star is 20 pc away from Earth.What is the stellar parallax for this star?

Accepted Answer

A)  6 arcsec 
B)  20 arcsec 
C)  0.02 arcsec 
D)  0.05 arcsec 
A)  6 arcsec 
B)  20 arcsec 
C)  0.02 arcsec 
D)  0.05 arcsec

Question 17

The luminosity of a star is a unique measure of its:

Accepted Answer

A)  total energy output. 
B)  velocity of recession away from us. 
C)  temperature. 
D)  physical size. 
A)  total energy output. 
B)  velocity of recession away from us. 
C)  temperature. 
D)  physical size.

Question 18

Light leaving a point source spreads out so that the apparent brightness I of light per unit area varies with distance d according to which law (   means "proportional to")?

Accepted Answer

A)  I = constant 
B)  I   1/d² 
C)  I   d² 
D)  I   1/d 
A)  I = constant 
B)  I   1/d² 
C)  I   d² 
D)  I   1/d

Question 19

Spectral types of stars (e.g.,O,B,A,F,G,K,and M)uniquely define their:

Accepted Answer

A)  sizes or radii. 
B)  absolute magnitudes. 
C)  luminosities. 
D)  surface temperatures. 
A)  sizes or radii. 
B)  absolute magnitudes. 
C)  luminosities. 
D)  surface temperatures.

Question 20

Aristotle (fourth century b.c.e.)rejected the idea that Earth moves because he knew stellar parallax motion would result,and he was unable to measure any.About how long after Aristotle was stellar parallax actually measured?

Accepted Answer

A)  two centuries 
B)  10 centuries 
C)  22 centuries 
D)  29 centuries 
A)  two centuries 
B)  10 centuries 
C)  22 centuries 
D)  29 centuries

A star that has an apparent magnitude of 0 (see Figure 10-2,Comins,Discovering the Essential Universe,6th ed.)would:

By examining a star's spectrum we can determine each of the following EXCEPT ONE.Which is the exception?

A star is at such a distance that its apparent magnitude (m)is 10 magnitudes fainter than its absolute magnitude (M).How far away is it?

It was discovered that stars of the same temperature can include stars of different radii.The response to this finding was to:

A star of apparent magnitude -2 appears _____ than a star of apparent magnitude -3.

A simple relationship exists between mass and luminosity for:

The equation for the luminosity of a star in terms of its surface temperature is L = (surface area)σT⁴,where σ is the Stefan-Boltzmann constant.This suggests that,when a plot is made of luminosities versus temperature:

The radial velocity curve of a star in a binary star system is a plot against time of the:

How far away is the nearest star beyond the Sun,in parsecs?

A particular star has an angle of parallax of 0.1 arcsec.What is the distance to this star?

A particular star appears fainter seen through a blue filter than seen through a yellow filter.Which surface temperature is possible for this star? (See Figure 10-4,Comins,Discovering the Essential Universe,6th ed.)

Suppose that two identical stars (they have the same total light output)are located so that star A is at a distance of 5 pc and star B is at a distance of 25 pc from Earth.How will star B appear,compared with star A?

What is the ONLY way to measure the mass of a star accurately?

A particular star is 20 pc away from Earth.What is the stellar parallax for this star?

The luminosity of a star is a unique measure of its:

Light leaving a point source spreads out so that the apparent brightness I of light per unit area varies with distance d according to which law ( means "proportional to")?

Spectral types of stars (e.g.,O,B,A,F,G,K,and M)uniquely define their:

Aristotle (fourth century b.c.e.)rejected the idea that Earth moves because he knew stellar parallax motion would result,and he was unable to measure any.About how long after Aristotle was stellar parallax actually measured?

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

A star that has an apparent magnitude of 0 (see Figure 10-2,Comins,Discovering the Essential Universe,6th ed.)would:

By examining a star's spectrum we can determine each of the following EXCEPT ONE.Which is the exception?

A star is at such a distance that its apparent magnitude (m)is 10 magnitudes fainter than its absolute magnitude (M).How far away is it?

It was discovered that stars of the same temperature can include stars of different radii.The response to this finding was to:

A star of apparent magnitude -2 appears _____ than a star of apparent magnitude -3.

A simple relationship exists between mass and luminosity for:

The equation for the luminosity of a star in terms of its surface temperature is L = (surface area)σT⁴,where σ is the Stefan-Boltzmann constant.This suggests that,when a plot is made of luminosities versus temperature:

The radial velocity curve of a star in a binary star system is a plot against time of the:

How far away is the nearest star beyond the Sun,in parsecs?

A particular star has an angle of parallax of 0.1 arcsec.What is the distance to this star?

A particular star appears fainter seen through a blue filter than seen through a yellow filter.Which surface temperature is possible for this star? (See Figure 10-4,Comins,Discovering the Essential Universe,6th ed.)

Suppose that two identical stars (they have the same total light output)are located so that star A is at a distance of 5 pc and star B is at a distance of 25 pc from Earth.How will star B appear,compared with star A?

What is the ONLY way to measure the mass of a star accurately?

A particular star is 20 pc away from Earth.What is the stellar parallax for this star?

The luminosity of a star is a unique measure of its:

Light leaving a point source spreads out so that the apparent brightness I of light per unit area varies with distance d according to which law ( means "proportional to")?

Spectral types of stars (e.g.,O,B,A,F,G,K,and M)uniquely define their:

Aristotle (fourth century b.c.e.)rejected the idea that Earth moves because he knew stellar parallax motion would result,and he was unable to measure any.About how long after Aristotle was stellar parallax actually measured?

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