Question 1

The Hertzsprung-Russell diagram is a graph of _________ for stars.

Accepted Answer

A)  mass versus brightness 
B)  size versus mass 
C)  luminosity versus temperature 
D)  mass versus spectral type 
E)  luminosity versus brightness 
A)  mass versus brightness 
B)  size versus mass 
C)  luminosity versus temperature 
D)  mass versus spectral type 
E)  luminosity versus brightness

Question 2

How is the distance to a star related to its parallax?

Accepted Answer

A)  Distance is directly proportional to parallax. 
B)  Distance is inversely proportional to parallax. 
C)  Distance is directly proportional to parallax squared. 
D)  Distance is inversely proportional to parallax squared. 
E)  Distance and parallax are not related to each other at all. 
A)  Distance is directly proportional to parallax. 
B)  Distance is inversely proportional to parallax. 
C)  Distance is directly proportional to parallax squared. 
D)  Distance is inversely proportional to parallax squared. 
E)  Distance and parallax are not related to each other at all.

Question 3

The stars that have the largest radii are classified as supergiants.

Accepted Answer

A) True 
 B)False

Question 4

Astronomers can measure the speed of the stars in a binary system by measuring the _________ of the stars.

Accepted Answer

A)  temperatures 
B)  luminosities 
C)  distance 
D)  colors 
E)  spectra 
A)  temperatures 
B)  luminosities 
C)  distance 
D)  colors 
E)  spectra

Question 5

Stars that have spectral type B are lower in temperature than spectral type M.

Accepted Answer

A) True 
 B)False

Question 6

You discover a binary star system in which star A has a velocity of 10 km/s and star B has a velocity of 30 km/s. If you study the system further and find out that the orbital period is 30 days and the orbital separation is a constant 0.3 AU, then what are the masses of stars A and B?

Accepted Answer

A)  Star A is 3M $\odot$ , and Star B is 1M $\odot$ . 
B)  Star A is 1M $\odot$ , and Star B is 0.3M $\odot$ . 
C)  Star A is 6M $\odot$ , and Star B is 2M $\odot$ . 
D)  Star A is 2M $\odot$ , and Star B is 0.5M $\odot$ . 
E)  Star A is 0.3M $\odot$ , and Star B is 1M $\odot$ 
A)  Star A is 3M $\odot$ , and Star B is 1M $\odot$ . 
B)  Star A is 1M $\odot$ , and Star B is 0.3M $\odot$ . 
C)  Star A is 6M $\odot$ , and Star B is 2M $\odot$ . 
D)  Star A is 2M $\odot$ , and Star B is 0.5M $\odot$ . 
E)  Star A is 0.3M $\odot$ , and Star B is 1M $\odot$

Question 7

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

Question 8

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 9

The picture 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 10

Main-sequence stars range in mass from approximately:

Accepted Answer

A)  0.5 to 10 M $\odot$ 
B)  0.08 to 150 M $\odot$ 
C)  1 to 100 M $\odot$ 
D)  0.1 to 75 M $\odot$ 
E)  5 to 50 M $\odot$ 
A)  0.5 to 10 M $\odot$ 
B)  0.08 to 150 M $\odot$ 
C)  1 to 100 M $\odot$ 
D)  0.1 to 75 M $\odot$ 
E)  5 to 50 M $\odot$

Question 11

Star A is exactly the same color as star B and appears equally bright. Through stellar parallax measurements, we find that star B is twice as far away from us as star A. Determine which star has the largest radius and how much larger it is.

Accepted Answer

For stars of equal brightness, luminosit

Question 12

Star A and star B both have the same temperature but different sizes and distances. As a result, star A is more luminous than star B, but star B is brighter than star A. Which of these statements about the absolute and apparent magnitudes of the two stars is correct?

Accepted Answer

A)  Star A has a larger apparent magnitude and a larger absolute magnitude. 
B)  Star A has a larger apparent magnitude, while star B has a larger absolute magnitude. 
C)  Star B has a larger apparent magnitude and a larger absolute magnitude. 
D)  Star B has a larger apparent magnitude, while star A has a larger absolute magnitude. 
E)  Both stars have the same apparent and absolute magnitudes. 
A)  Star A has a larger apparent magnitude and a larger absolute magnitude. 
B)  Star A has a larger apparent magnitude, while star B has a larger absolute magnitude. 
C)  Star B has a larger apparent magnitude and a larger absolute magnitude. 
D)  Star B has a larger apparent magnitude, while star A has a larger absolute magnitude. 
E)  Both stars have the same apparent and absolute magnitudes.

Question 13

The absolute magnitude of a star is a measure of its luminosity.

Accepted Answer

A) True 
 B)False

Question 14

Stars of spectral class O have the strongest hydrogen absorption lines, whereas stars of spectral class M have the weakest hydrogen absorption lines.

Accepted Answer

A) True 
 B)False

Question 15

If a star's measured parallax is 0.2 arcsec, what is its distance?

Accepted Answer

A)  2 pc 
B)  5 pc 
C)  20 pc 
D)  40 pc 
E)  50 pc 
A)  2 pc 
B)  5 pc 
C)  20 pc 
D)  40 pc 
E)  50 pc

Question 16

A star with a stellar parallax of 0.025 arcseconds has a distance of how many parsecs?

Accepted Answer

The inverse of stellar paralla

Question 17

If a star's parallax is measured using identical telescopes, one on Earth and the other on Mars, which planet's telescope would measure the biggest parallax? Explain your answer.

Accepted Answer

The telescope on Mars would measure a la

Question 18

What is the difference between brightness and luminosity?

Accepted Answer

A)  These are different names for the same property. 
B)  Luminosity is how much light we see from a star; brightness is how much light it emits. 
C)  Brightness is how much light we see from a star; luminosity is how much light it emits. 
D)  Luminosity measures size; brightness measures temperature. 
E)  Brightness measure size; luminosity measures temperature. 
A)  These are different names for the same property. 
B)  Luminosity is how much light we see from a star; brightness is how much light it emits. 
C)  Brightness is how much light we see from a star; luminosity is how much light it emits. 
D)  Luminosity measures size; brightness measures temperature. 
E)  Brightness measure size; luminosity measures temperature.

Question 19

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)  Star E has twice the radius of star F. 
B)  Star E has four times the radius of star F. 
C)  Star F has twice the radius of star E. 
D)  Star F has four times the radius of star E. 
E)  They are the same size. 
A)  Star E has twice the radius of star F. 
B)  Star E has four times the radius of star F. 
C)  Star F has twice the radius of star E. 
D)  Star F has four times the radius of star E. 
E)  They are the same size.

Question 20

Rigel is a star with an apparent magnitude of +0.1, and Betelgeuse is a star with an apparent magnitude of +0.4. Which star appears brighter, and what is the ratio of their brightnesses?

Accepted Answer

Rigel is brighter than Betelge

Exam 13: Taking the Measure of Stars

The Hertzsprung-Russell diagram is a graph of _________ for stars.

How is the distance to a star related to its parallax?

The stars that have the largest radii are classified as supergiants.

Astronomers can measure the speed of the stars in a binary system by measuring the _________ of the stars.

Stars that have spectral type B are lower in temperature than spectral type M.

You discover a binary star system in which star A has a velocity of 10 km/s and star B has a velocity of 30 km/s. If you study the system further and find out that the orbital period is 30 days and the orbital separation is a constant 0.3 AU, then what are the masses of stars A and B?

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.

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

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

Main-sequence stars range in mass from approximately:

Star A is exactly the same color as star B and appears equally bright. Through stellar parallax measurements, we find that star B is twice as far away from us as star A. Determine which star has the largest radius and how much larger it is.

Star A and star B both have the same temperature but different sizes and distances. As a result, star A is more luminous than star B, but star B is brighter than star A. Which of these statements about the absolute and apparent magnitudes of the two stars is correct?

The absolute magnitude of a star is a measure of its luminosity.

Stars of spectral class O have the strongest hydrogen absorption lines, whereas stars of spectral class M have the weakest hydrogen absorption lines.

If a star's measured parallax is 0.2 arcsec, what is its distance?

A star with a stellar parallax of 0.025 arcseconds has a distance of how many parsecs?

If a star's parallax is measured using identical telescopes, one on Earth and the other on Mars, which planet's telescope would measure the biggest parallax? Explain your answer.

What is the difference between brightness and luminosity?

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?

Rigel is a star with an apparent magnitude of +0.1, and Betelgeuse is a star with an apparent magnitude of +0.4. Which star appears brighter, and what is the ratio of their brightnesses?

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Our Starthe Sun

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

Large-Scale Structure in the Universe

Life

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