Question 1

If a nearby star shows a parallax of 0.5 arcsec (when Earth moves through 1 AU,by definition),what is its distance from Earth,in light-years?

Accepted Answer

A)  2 ly 
B)  1.83 ly 
C)  6.52 ly 
D)  3.26 ly 
A)  2 ly 
B)  1.83 ly 
C)  6.52 ly 
D)  3.26 ly

Question 2

What is the fundamental difference between absolute and apparent magnitude of a star?

Accepted Answer

A)  The difference is +5 since absolute and apparent magnitude differ by this value by definition. 
B)  Apparent magnitude depends on the star's temperature, whereas absolute magnitude is independent of temperature. 
C)  Apparent magnitude depends on the size of the star, whereas absolute magnitude is independent of this parameter. 
D)  Absolute magnitude is an intrinsic property of the star, whereas apparent magnitude depends on its distance from Earth. 
A)  The difference is +5 since absolute and apparent magnitude differ by this value by definition. 
B)  Apparent magnitude depends on the star's temperature, whereas absolute magnitude is independent of temperature. 
C)  Apparent magnitude depends on the size of the star, whereas absolute magnitude is independent of this parameter. 
D)  Absolute magnitude is an intrinsic property of the star, whereas apparent magnitude depends on its distance from Earth.

Question 3

A particular star is at a distance of 20 pc from Earth.For this star,the apparent magnitude will have:

Accepted Answer

A)  a larger value than its absolute magnitude. 
B)  a smaller value than its absolute magnitude. 
C)  the same value as its absolute magnitude, since magnitude is independent of distance. 
D)  a larger or a smaller value than the absolute magnitude, depending on the temperature and diameter of the star. 
A)  a larger value than its absolute magnitude. 
B)  a smaller value than its absolute magnitude. 
C)  the same value as its absolute magnitude, since magnitude is independent of distance. 
D)  a larger or a smaller value than the absolute magnitude, depending on the temperature and diameter of the star.

Question 4

How is stellar parallax defined?

Accepted Answer

A)  Stellar parallax is the angle taken up by the diameter of a star as seen from Earth. 
B)  Stellar parallax is the angle subtended by the radius of Earth's orbit as seen from the star. 
C)  Stellar parallax is the angle subtended by the diameter of Earth's orbit as seen from the star. 
D)  Stellar parallax is the angle through which a star moves in our sky over the course of 1 year due to the motion of both the star and Earth. 
A)  Stellar parallax is the angle taken up by the diameter of a star as seen from Earth. 
B)  Stellar parallax is the angle subtended by the radius of Earth's orbit as seen from the star. 
C)  Stellar parallax is the angle subtended by the diameter of Earth's orbit as seen from the star. 
D)  Stellar parallax is the angle through which a star moves in our sky over the course of 1 year due to the motion of both the star and Earth.

Question 5

The light curve made of a pair of eclipsing binaries will exhibit dips in intensity.The bottoms of these dips can have different shapes.How do we interpret this?

Accepted Answer

A)  A flat bottom means that we are viewing the system along the long (semimajor) axis. 
B)  A flat bottom means that the stars are experiencing a total eclipse. 
C)  A rounded bottom means that the stars are exhibiting a partial eclipse. 
D)  A V-shaped bottom means that we are viewing the system along the short (semiminor) axis. 
A)  A flat bottom means that we are viewing the system along the long (semimajor) axis. 
B)  A flat bottom means that the stars are experiencing a total eclipse. 
C)  A rounded bottom means that the stars are exhibiting a partial eclipse. 
D)  A V-shaped bottom means that we are viewing the system along the short (semiminor) axis.

Question 6

The Hipparcos satellite could measure stars up to approximately 150 pc away.What was the smallest parallax angle it could measure?

Accepted Answer

A)  150 arcsec 
B)  1/150 arcsec 
C)  1/150 degrees 
D)  1/75 arcsec 
A)  150 arcsec 
B)  1/150 arcsec 
C)  1/150 degrees 
D)  1/75 arcsec

Question 7

Absorption-line strengths are used in the spectral classification of stars and the determination of surface temperatures.Which atomic or molecular constituent exhibits strong absorption lines in spectra from stars with very high surface temperature?

Accepted Answer

A)  H 
B)  Ca II 
C)  He II 
D)  TiO 
A)  H 
B)  Ca II 
C)  He II 
D)  TiO

Question 8

How many stars (other than the Sun)have an angle of parallax greater than 1 second of arc?

Accepted Answer

A)  about a hundred 
B)  millions 
C)  none 
D)  only one 
A)  about a hundred 
B)  millions 
C)  none 
D)  only one

Question 9

Using the Hertzsprung-Russell diagram (Figure 10-7 of Comins,Discovering the Essential Universe,6th ed.),determine which type of star has the following characteristics: surface temperature of 40,000 K,luminosity 100,000 times that of the Sun.

Accepted Answer

A)  a cool, red, main-sequence star 
B)  a hot, blue, main-sequence star 
C)  a white dwarf 
D)  a red giant 
A)  a cool, red, main-sequence star 
B)  a hot, blue, main-sequence star 
C)  a white dwarf 
D)  a red giant

Question 10

Development of the Henry Draper Catalog of stellar classifications was begun in the late nineteenth century.The catalog originally classified stars according to the strengths of their hydrogen lines.By the 1920s,however,the sequence had been reorganized so that the stars were classified by surface temperature.What important scientific development made possible this reinterpretation?

Accepted Answer

A)  the discovery of nuclear physics and how stars generate their energy 
B)  the discovery of blackbody radiation and the blackbody curve 
C)  the development of atomic physics and how atoms emit light 
D)  the development of radio astronomy and the detection of molecules in space 
A)  the discovery of nuclear physics and how stars generate their energy 
B)  the discovery of blackbody radiation and the blackbody curve 
C)  the development of atomic physics and how atoms emit light 
D)  the development of radio astronomy and the detection of molecules in space

Question 11

A particular star has an absolute magnitude of +12 and a spectral class of A5.Using Figures 10-7 and 10-10 of Comins,Discovering the Essential Universe,6th ed.,how would this star be classified?

Accepted Answer

A)  A5 I 
B)  A-type white dwarf 
C)  A5 V 
D)  A5 III 
A)  A5 I 
B)  A-type white dwarf 
C)  A5 V 
D)  A5 III

Question 12

As you move upward and to the left on the H-R diagram,the stars become:

Accepted Answer

A)  cooler and redder. 
B)  hotter and redder. 
C)  cooler and whiter. 
D)  hotter and whiter. 
A)  cooler and redder. 
B)  hotter and redder. 
C)  cooler and whiter. 
D)  hotter and whiter.

Question 13

In the spectral classification scheme,what designation is given to a star just a little cooler than a K5 star?

Accepted Answer

A)  K4 
B)  K6 
C)  M0 
D)  K0 
A)  K4 
B)  K6 
C)  M0 
D)  K0

Question 14

By what standard technique do astronomers find the luminosity class (I,II,III,IV,or V)of a star?

Accepted Answer

A)  combining the apparent magnitude with the measured distance to the star 
B)  observing the diameter of the star on a photographic plate or CCD image 
C)  timing how long it takes for the star to be eclipsed by a companion in an eclipsing binary star system 
D)  studying the absorption lines in the star's spectrum 
A)  combining the apparent magnitude with the measured distance to the star 
B)  observing the diameter of the star on a photographic plate or CCD image 
C)  timing how long it takes for the star to be eclipsed by a companion in an eclipsing binary star system 
D)  studying the absorption lines in the star's spectrum

Question 15

A star whose absolute magnitude M is +2.2 is seen to have an apparent magnitude when viewed from Earth of +5.2.According to the equation in Discovery 10-2 in Comins,Discovering the Essential Universe,6th ed.,how far away is the star?

Accepted Answer

A)  40 pc 
B)  12.3 pc 
C)  130 pc 
D)  3/5, or 0.6 pc 
A)  40 pc 
B)  12.3 pc 
C)  130 pc 
D)  3/5, or 0.6 pc

Question 16

How much can we learn about a star from a measurement of its apparent magnitude?

Accepted Answer

A)  its intrinsic brightness (the total light actually emitted by the star) 
B)  the brightness the star would appear to have if it were exactly 10 pc from Earth 
C)  the brightness of the star as it appears in Earth's sky 
D)  the total output of electromagnetic energy emitted at all wavelengths from the star 
A)  its intrinsic brightness (the total light actually emitted by the star) 
B)  the brightness the star would appear to have if it were exactly 10 pc from Earth 
C)  the brightness of the star as it appears in Earth's sky 
D)  the total output of electromagnetic energy emitted at all wavelengths from the star

Question 17

Is there a relationship between the mass of a main sequence star and its luminosity?

Accepted Answer

A)  No. Large masses can have low luminosities and vice versa. 
B)  Yes, mass and luminosity are related linearly: A star twice as massive has twice the luminosity. 
C)  Yes, the mass and luminosity are related, but not linearly: A star twice as massive has more than twice the luminosity. 
D)  Yes, but surprisingly there is an anti-correlation: Larger masses have smaller luminosities. 
A)  No. Large masses can have low luminosities and vice versa. 
B)  Yes, mass and luminosity are related linearly: A star twice as massive has twice the luminosity. 
C)  Yes, the mass and luminosity are related, but not linearly: A star twice as massive has more than twice the luminosity. 
D)  Yes, but surprisingly there is an anti-correlation: Larger masses have smaller luminosities.

Question 18

Which property(ies)of a nearby star is/are determined by a measurement of stellar parallax?

Accepted Answer

A)  spectral type and surface temperature 
B)  rotation period 
C)  apparent magnitude 
D)  distance from Earth 
A)  spectral type and surface temperature 
B)  rotation period 
C)  apparent magnitude 
D)  distance from Earth

Question 19

In the Hertzsprung-Russell diagram in Figure 10-7 of Comins,Discovering the Essential Universe,6th ed.,which list is the CORRECT sequence of stars in order of increasing temperature?

Accepted Answer

A)  Sirius B, Deneb, Procyon B, the Sun 
B)  Deneb, the Sun, Sirius B, Procyon B 
C)  Sun, Procyon B, Deneb, Sirius B 
D)  Procyon B, Sirius B, the Sun, Deneb 
A)  Sirius B, Deneb, Procyon B, the Sun 
B)  Deneb, the Sun, Sirius B, Procyon B 
C)  Sun, Procyon B, Deneb, Sirius B 
D)  Procyon B, Sirius B, the Sun, Deneb

Question 20

The Sun's classification in terms of its surface temperature,as determined from absorption lines in its spectrum,is:

Accepted Answer

A)  M9. 
B)  G2. 
C)  O1. 
D)  B2. 
A)  M9. 
B)  G2. 
C)  O1. 
D)  B2.

If a nearby star shows a parallax of 0.5 arcsec (when Earth moves through 1 AU,by definition),what is its distance from Earth,in light-years?

What is the fundamental difference between absolute and apparent magnitude of a star?

A particular star is at a distance of 20 pc from Earth.For this star,the apparent magnitude will have:

How is stellar parallax defined?

The light curve made of a pair of eclipsing binaries will exhibit dips in intensity.The bottoms of these dips can have different shapes.How do we interpret this?

The Hipparcos satellite could measure stars up to approximately 150 pc away.What was the smallest parallax angle it could measure?

Absorption-line strengths are used in the spectral classification of stars and the determination of surface temperatures.Which atomic or molecular constituent exhibits strong absorption lines in spectra from stars with very high surface temperature?

How many stars (other than the Sun)have an angle of parallax greater than 1 second of arc?

Using the Hertzsprung-Russell diagram (Figure 10-7 of Comins,Discovering the Essential Universe,6th ed.),determine which type of star has the following characteristics: surface temperature of 40,000 K,luminosity 100,000 times that of the Sun.

A particular star has an absolute magnitude of +12 and a spectral class of A5.Using Figures 10-7 and 10-10 of Comins,Discovering the Essential Universe,6th ed.,how would this star be classified?

As you move upward and to the left on the H-R diagram,the stars become:

In the spectral classification scheme,what designation is given to a star just a little cooler than a K5 star?

By what standard technique do astronomers find the luminosity class (I,II,III,IV,or V)of a star?

A star whose absolute magnitude M is +2.2 is seen to have an apparent magnitude when viewed from Earth of +5.2.According to the equation in Discovery 10-2 in Comins,Discovering the Essential Universe,6th ed.,how far away is the star?

How much can we learn about a star from a measurement of its apparent magnitude?

Is there a relationship between the mass of a main sequence star and its luminosity?

Which property(ies)of a nearby star is/are determined by a measurement of stellar parallax?

In the Hertzsprung-Russell diagram in Figure 10-7 of Comins,Discovering the Essential Universe,6th ed.,which list is the CORRECT sequence of stars in order of increasing temperature?

The Sun's classification in terms of its surface temperature,as determined from absorption lines in its spectrum,is:

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 a nearby star shows a parallax of 0.5 arcsec (when Earth moves through 1 AU,by definition),what is its distance from Earth,in light-years?

What is the fundamental difference between absolute and apparent magnitude of a star?

A particular star is at a distance of 20 pc from Earth.For this star,the apparent magnitude will have:

How is stellar parallax defined?

The light curve made of a pair of eclipsing binaries will exhibit dips in intensity.The bottoms of these dips can have different shapes.How do we interpret this?

The Hipparcos satellite could measure stars up to approximately 150 pc away.What was the smallest parallax angle it could measure?

Absorption-line strengths are used in the spectral classification of stars and the determination of surface temperatures.Which atomic or molecular constituent exhibits strong absorption lines in spectra from stars with very high surface temperature?

How many stars (other than the Sun)have an angle of parallax greater than 1 second of arc?

Using the Hertzsprung-Russell diagram (Figure 10-7 of Comins,Discovering the Essential Universe,6th ed.),determine which type of star has the following characteristics: surface temperature of 40,000 K,luminosity 100,000 times that of the Sun.

A particular star has an absolute magnitude of +12 and a spectral class of A5.Using Figures 10-7 and 10-10 of Comins,Discovering the Essential Universe,6th ed.,how would this star be classified?

As you move upward and to the left on the H-R diagram,the stars become:

In the spectral classification scheme,what designation is given to a star just a little cooler than a K5 star?

By what standard technique do astronomers find the luminosity class (I,II,III,IV,or V)of a star?

A star whose absolute magnitude M is +2.2 is seen to have an apparent magnitude when viewed from Earth of +5.2.According to the equation in Discovery 10-2 in Comins,Discovering the Essential Universe,6th ed.,how far away is the star?

How much can we learn about a star from a measurement of its apparent magnitude?

Is there a relationship between the mass of a main sequence star and its luminosity?

Which property(ies)of a nearby star is/are determined by a measurement of stellar parallax?

In the Hertzsprung-Russell diagram in Figure 10-7 of Comins,Discovering the Essential Universe,6th ed.,which list is the CORRECT sequence of stars in order of increasing temperature?

The Sun's classification in terms of its surface temperature,as determined from absorption lines in its spectrum,is:

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