Question 1

Compare and contrast stars on the upper left and lower right of the main sequence.

Accepted Answer

Stars on the upper left are type O and B. They are hotter, more massive and luminous, have larger radii, are blue- white or white, and have relatively short lifetimes. The hottest, type O, have lines of ionized helium. Stars on the lower right are cooler, less massive and luminous, are smaller and redder, and have very long lifetimes. The coolest have molecular spectral lines.

Question 2

In the H- R diagram, what are the two most important types of data plotted?

Accepted Answer

A)   absolute and apparent magnitudes
B)   spectral classes and absolute magnitudes
C)   apparent magnitudes and temperatures
D)   luminosities and masses
E)   sizes and temperatures B

Question 3

How can Betelgeuse be only half the Sun's surface temperature, yet about 10,000 times more luminous than the hotter Sun?

Accepted Answer

It may be cooler, but it is ab...

Question 4

To find the _ velocity, we must combine proper motion and parallax data.

Accepted Answer

The answer of To find the _ velocity, we must...

Question 5

A star has a parallax of 0.01 arc seconds. Its distance is

Accepted Answer

A)   10 parsecs
B)   100 parsecs.
C)   1 parsec.
D)   0.1 parsecs.
E)   0.01 parsecs.

Question 6

Two stars both have parallaxes of 0.023", but star A has apparent magnitude +2.3, while star B is magnitude +7.3. Which statement is true?

Accepted Answer

A)   Star A is both 100× brighter and larger than star B.
B)   Star B must be ten times more luminous.
C)   Star A must be ten times closer.
D)   Star A is both 100× brighter and more luminous than star B.
E)   Nothing, since we do not know their absolute magnitudes.

Question 7

The ionized helium lines show up only in class stars.

Accepted Answer

A)   M
B)   K
C)   O
D)   B
E)   F

Question 8

The distance to a star with a parallax angle of 0.2 arc seconds is

Accepted Answer

A)   0.2 parsec.
B)   2 parsecs.
C)   5 parsecs.
D)   12 parsecs.
E)   20 parsecs. C

Question 9

The stars a Cygni and fi Cygni are in the constellation Cygnus. Which statement is true?

Accepted Answer

A)   a Cygni appears brighter.
B)   fi is hotter.
C)   fi Cygni appears brighter.
D)   a must be the eastern most star in the constellation.
E)   fi appears redder.

Question 10

What role do molecules play in spectral classification?

Accepted Answer

Molecules can only f...

Question 11

On the H- R diagram, white dwarfs Sirius B and Procyon B lie

Accepted Answer

A)   at the top right.
B)   close to the Sun, near the center.
C)   at the lower left.
D)   at the lower right.
E)   at the top left.

Question 12

Which of these stars would be the hottest?

Accepted Answer

A)   M10
B)   G2
C)   B0
D)   A0
E)   K9

Question 13

In addition to the proper motion, we also need the to find the transverse velocity of a star across our line of sight.

Accepted Answer

A)   temperature
B)   parallax
C)   composition
D)   mass
E)   color

Question 14

Binary stars separated enough to be resolved in a telescope are called

Accepted Answer

A)   line- of- sight binaries.
B)   astrometric binaries.
C)   spectroscopic binaries.
D)   visual binaries.
E)   orbital binaries.

Question 15

Stellar masses are measured directly by observations of the motions of

Accepted Answer

A)   eclipsing binary systems.
B)   visual binary systems.
C)   spectroscopic binary systems.
D)   All of the above can give us their masses.
E)   Stellar masses cannot be measured directly by any method.

Question 16

In the M class stars, we find _ absorption lines not seen in hotter stars.

Accepted Answer

The answer of In the M class stars, we find...

Question 17

A type B star is bluer than a type G star.

Accepted Answer

A) True 
 B)False

Question 18

Why is the main sequence main? Why are these stars so common?

Accepted Answer

While their masses, luminosities, and te...

Question 19

A unique characteristic of type O stars is ionized helium lines in its spectrum.

Accepted Answer

A) True 
 B)False

Question 20

A star's absolute magnitude is its apparent brightness as seen from

Accepted Answer

A)   Alpha Centauri.
B)   10 light- years distance.
C)   Pluto.
D)   100 parsecs distance.
E)   10 parsecs distance.

Exam 11: Measuring the Stars: Giants, Dwarfs, and the Main Sequence

Compare and contrast stars on the upper left and lower right of the main sequence.

In the H- R diagram, what are the two most important types of data plotted?

Correct Answer
verified
B

How can Betelgeuse be only half the Sun's surface temperature, yet about 10,000 times more luminous than the hotter Sun?

Correct Answer
verified
It may be cooler, but it is ab...
View Answer

To find the _ velocity, we must combine proper motion and parallax data.

Correct Answer
verified

A star has a parallax of 0.01 arc seconds. Its distance is

Correct Answer
verified

Two stars both have parallaxes of 0.023", but star A has apparent magnitude +2.3, while star B is magnitude +7.3. Which statement is true?

Correct Answer
verified

The ionized helium lines show up only in class stars.

Correct Answer
verified

The distance to a star with a parallax angle of 0.2 arc seconds is

Correct Answer
verified
C

The stars a Cygni and fi Cygni are in the constellation Cygnus. Which statement is true?

Correct Answer
verified

What role do molecules play in spectral classification?

Correct Answer
verified
Molecules can only f...
View Answer

On the H- R diagram, white dwarfs Sirius B and Procyon B lie

Correct Answer
verified

Which of these stars would be the hottest?

Correct Answer
verified

In addition to the proper motion, we also need the to find the transverse velocity of a star across our line of sight.

Correct Answer
verified

Binary stars separated enough to be resolved in a telescope are called

Correct Answer
verified

Stellar masses are measured directly by observations of the motions of

Correct Answer
verified

In the M class stars, we find _ absorption lines not seen in hotter stars.

Correct Answer
verified

A type B star is bluer than a type G star.

Correct Answer
verified

Why is the main sequence main? Why are these stars so common?

Correct Answer
verified
While their masses, luminosities, and te...
View Answer

A unique characteristic of type O stars is ionized helium lines in its spectrum.

Correct Answer
verified

A star's absolute magnitude is its apparent brightness as seen from

Correct Answer
verified

Exam 11: Measuring the Stars: Giants, Dwarfs, and the Main Sequence

Compare and contrast stars on the upper left and lower right of the main sequence.

In the H- R diagram, what are the two most important types of data plotted?

Correct AnswerverifiedB

How can Betelgeuse be only half the Sun's surface temperature, yet about 10,000 times more luminous than the hotter Sun?

Correct AnswerverifiedIt may be cooler, but it is ab...View AnswerShow Answer

To find the _ velocity, we must combine proper motion and parallax data.

Correct AnswerverifiedShow Answer

A star has a parallax of 0.01 arc seconds. Its distance is

Correct AnswerverifiedShow Answer

Two stars both have parallaxes of 0.023", but star A has apparent magnitude +2.3, while star B is magnitude +7.3. Which statement is true?

Correct AnswerverifiedShow Answer

The ionized helium lines show up only in class stars.

Correct AnswerverifiedShow Answer

The distance to a star with a parallax angle of 0.2 arc seconds is

Correct AnswerverifiedC

The stars a Cygni and fi Cygni are in the constellation Cygnus. Which statement is true?

Correct AnswerverifiedShow Answer

What role do molecules play in spectral classification?

Correct AnswerverifiedMolecules can only f...View AnswerShow Answer

On the H- R diagram, white dwarfs Sirius B and Procyon B lie

Correct AnswerverifiedShow Answer

Which of these stars would be the hottest?

Correct AnswerverifiedShow Answer

In addition to the proper motion, we also need the to find the transverse velocity of a star across our line of sight.

Correct AnswerverifiedShow Answer

Binary stars separated enough to be resolved in a telescope are called

Correct AnswerverifiedShow Answer

Stellar masses are measured directly by observations of the motions of

Correct AnswerverifiedShow Answer

In the M class stars, we find _ absorption lines not seen in hotter stars.

Correct AnswerverifiedShow Answer

A type B star is bluer than a type G star.

Correct AnswerverifiedShow Answer

Why is the main sequence main? Why are these stars so common?

Correct AnswerverifiedWhile their masses, luminosities, and te...View AnswerShow Answer

A unique characteristic of type O stars is ionized helium lines in its spectrum.

Correct AnswerverifiedShow Answer

A star's absolute magnitude is its apparent brightness as seen from

Correct AnswerverifiedShow Answer

Correct Answer
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B

Correct Answer
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It may be cooler, but it is ab...
View Answer

Correct Answer
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Correct Answer
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Correct Answer
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C

Correct Answer
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Correct Answer
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Molecules can only f...
View Answer

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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While their masses, luminosities, and te...
View Answer

Correct Answer
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Correct Answer
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