Question 1

Procyon lies about 13 light years distant,thus its parallax is about:

Accepted Answer

A)  0.01". 
B)  0.25". 
C)  0.40". 
D)  0.65". 
E)  1.3". 
A)  0.01". 
B)  0.25". 
C)  0.40". 
D)  0.65". 
E)  1.3".

Question 2

About 500 stars can be seen by the naked eye from somewhere on Earth.

Accepted Answer

A) True 
 B)False

Question 3

Eclipsing binaries are the most useful,giving us sizes as well as masses of the pair.

Accepted Answer

A) True 
 B)False

Question 4

In comparing first magnitude Deneb with second magnitude Polaris,we find that:

Accepted Answer

A)  Polaris is in reality much more luminous. 
B)  Deneb must be much hotter than Polaris. 
C)  Deneb appears 2.5 times brighter to us than does Polaris. 
D)  Polaris is really 100 times brighter than nearby Deneb. 
E)  Deneb is really much closer than Polaris. 
A)  Polaris is in reality much more luminous. 
B)  Deneb must be much hotter than Polaris. 
C)  Deneb appears 2.5 times brighter to us than does Polaris. 
D)  Polaris is really 100 times brighter than nearby Deneb. 
E)  Deneb is really much closer than Polaris.

Question 5

How is proper motion measured?

Accepted Answer

It is the apparent motion of t

Question 6

Star A and star B both have an absolute magnitude of 2.0,but star A has an apparent magnitude of 5.0 and star B has an apparent magnitude of 7.0.Which statement below is correct?

Accepted Answer

A)  Star A appears brighter than star B, but actually star B and star A are the same brightness. 
B)  Star B appears brighter than star A, but actually star B and star A are the same brightness. 
C)  Star A and star B appear to have the same brightness, but actually star B is brighter than star A. 
D)  Star A and star B appear to have the same brightness, but actually star A is brighter than star B. 
E)  It is impossible to determine how bright these stars are or appear to be relative to one another, given the information above. 
A)  Star A appears brighter than star B, but actually star B and star A are the same brightness. 
B)  Star B appears brighter than star A, but actually star B and star A are the same brightness. 
C)  Star A and star B appear to have the same brightness, but actually star B is brighter than star A. 
D)  Star A and star B appear to have the same brightness, but actually star A is brighter than star B. 
E)  It is impossible to determine how bright these stars are or appear to be relative to one another, given the information above.

Question 7

What role does hydrogen play in spectral classification?

Accepted Answer

It is most prominent

Question 8

A star similar to Sirius A has a temperature of about 10,000 K,and a luminosity of around 25 times that of the Sun.Approximately what is its radius?

Accepted Answer

Using T in units of 5000 K,that gives T=

Question 9

Capella is the same temperature as our Sun,but about ten times the Sun's diameter; it must be about ________ times as luminous as our star.

Accepted Answer

The answer of Capella is the same temperature as our...

Question 10

Explain how the shifting spectral lines of spectroscopic binaries let us find their periods.

Accepted Answer

When aligned in our line of sight,there

Question 11

About how many stars can be seen from somewhere on Earth with the naked eye?

Accepted Answer

A)  600 
B)  6,000 
C)  600,000 
D)  6,000,000 
E)  Uncountably many 
A)  600 
B)  6,000 
C)  600,000 
D)  6,000,000 
E)  Uncountably many

Question 12

Alpha Centauri A and B have an average orbital separation of about 23 AU and a period of about 80 years.Approximately what is the sum of their masses? If we presume that Alpha Centauri A is a star like our Sun,what is Alpha Centauri B's mass?

Accepted Answer

M = a³ / P² = 23³ /

Question 13

The Sun's complete classification is G2V.

Accepted Answer

A) True 
 B)False

Question 14

Knowledge of a star's temperature and ________ enables us to calculate its radius,surface area,and volume from the appropriate radiation law.

Accepted Answer

luminosity

Question 15

What is the relationship between a star's mass and its lifetime?

Accepted Answer

The more massive a s

Question 16

What is the typical main sequence lifetime of a B-type star?

Accepted Answer

A)  less than a million years 
B)  20 million years 
C)  100 million years 
D)  1 billion years 
E)  10 billion years 
A)  less than a million years 
B)  20 million years 
C)  100 million years 
D)  1 billion years 
E)  10 billion years

Question 17

Which statement about stellar motion is incorrect?

Accepted Answer

A)  In general, the closer a star is, the more its proper motion. 
B)  The radial velocity is measured by the Doppler shift. 
C)  The transverse velocity is measured by the proper motion and the distance. 
D)  Like parallax, proper motion is measured over intervals of exactly six months. 
E)  The Pythagorean theorem relates space, transverse, and radial velocities. 
A)  In general, the closer a star is, the more its proper motion. 
B)  The radial velocity is measured by the Doppler shift. 
C)  The transverse velocity is measured by the proper motion and the distance. 
D)  Like parallax, proper motion is measured over intervals of exactly six months. 
E)  The Pythagorean theorem relates space, transverse, and radial velocities.

Question 18

Like the Sun,main sequence stars are converting hydrogen into helium in their cores.

Accepted Answer

A) True 
 B)False

Question 19

In a visual binary system with circular orbits,if in 20 years the two stars' position angles have shifted by 30 degrees,the pair's period must be:

Accepted Answer

A)  60 years. 
B)  90 years. 
C)  120 years. 
D)  240 years. 
E)  360 years. 
A)  60 years. 
B)  90 years. 
C)  120 years. 
D)  240 years. 
E)  360 years.

Question 20

A type B9 star is hotter than a type A0.

Accepted Answer

A) True 
 B)False

Exam 17: The Stars: Giants,Dwarfs,and the Main Sequence

Procyon lies about 13 light years distant,thus its parallax is about:

About 500 stars can be seen by the naked eye from somewhere on Earth.

Eclipsing binaries are the most useful,giving us sizes as well as masses of the pair.

In comparing first magnitude Deneb with second magnitude Polaris,we find that:

How is proper motion measured?

Star A and star B both have an absolute magnitude of 2.0,but star A has an apparent magnitude of 5.0 and star B has an apparent magnitude of 7.0.Which statement below is correct?

What role does hydrogen play in spectral classification?

A star similar to Sirius A has a temperature of about 10,000 K,and a luminosity of around 25 times that of the Sun.Approximately what is its radius?

Capella is the same temperature as our Sun,but about ten times the Sun's diameter; it must be about ________ times as luminous as our star.

Explain how the shifting spectral lines of spectroscopic binaries let us find their periods.

About how many stars can be seen from somewhere on Earth with the naked eye?

Alpha Centauri A and B have an average orbital separation of about 23 AU and a period of about 80 years.Approximately what is the sum of their masses? If we presume that Alpha Centauri A is a star like our Sun,what is Alpha Centauri B's mass?

The Sun's complete classification is G2V.

Knowledge of a star's temperature and ________ enables us to calculate its radius,surface area,and volume from the appropriate radiation law.

What is the relationship between a star's mass and its lifetime?

What is the typical main sequence lifetime of a B-type star?

Which statement about stellar motion is incorrect?

Like the Sun,main sequence stars are converting hydrogen into helium in their cores.

In a visual binary system with circular orbits,if in 20 years the two stars' position angles have shifted by 30 degrees,the pair's period must be:

A type B9 star is hotter than a type A0.

Charting the Heavens: The Foundations of Astronomy

The Copernican Revolution: The Birth of Modern Science

Radiation: Information from the Cosmos

Spectroscopy: The Inner Workings of Atoms

Telescopes: The Tools of Astronomy

The Solar System: Comparative Planetology and Formation Models

Earth: Our Home in Space

The Moon and Mercury: Scorched and Battered Worlds

Venus: Earth's Sister Planet

Mars: A Near Miss for Life?

Jupiter: Giant of the Solar System

Saturn: Spectacular Rings and Mysterious Moons

Uranus and Neptune: The Outer Worlds of the Solar System

Solar System Debris: Keys to Our Origin

Exoplanets: Planetary Systems Beyond Our Own

The Sun: Our Parent Star

The Interstellar Medium: Gas and Dust among the Stars

Star Formation: A Traumatic Birth

Stellar Evolution: The Life and Death of a Star

Stellar Explosions: Novae,Supernovae,and the Formation of the Elements

Neutron Stars and Black Holes: Strange States of Matter

The Milky Way Galaxy: A Spiral in Space

Galaxies: Building Blocks of the Universe

Galaxies and Dark Matter: The Large-Scale Structure of the Cosmos

Cosmology: The Big Bang and the Fate of the Universe

The Early Universe: Toward the Beginning of Time

Life in the Universe: Are We Alone?

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