Question 1

Stars X and Y are 5 AU apart from each other.Star X is four times as massive as star Y.The center of mass of this system is _________ AU away from star X and _________ AU away from star Y.

Accepted Answer

A) 3;2 
B) 2;3 
C) 2.5;2.5 
D) 1;4 
E) 4;1

Question 2

Star A is a red star.Star B is a blue star.You are able to determine that both stars are the same size.Which star is brighter?

Accepted Answer

A) Star A is brighter. 
B) Star B is brighter. 
C) They have the same brightness. 
D) We also need to know the distance of the stars to determine their brightness. 
E) Color is not related to brightness at all.

Question 3

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☉,and Star B is 1M☉. 
B) Star A is 1M☉,and Star B is 0.3M☉. 
C) Star A is 6M☉,and Star B is 2M☉. 
D) Star A is 2M☉,and Star B is 0.5M☉. 
E) Star A is 0.3M☉,and Star B is 1M☉.

Question 4

What is the main property of a main-sequence star that determines all its other properties?

Accepted Answer

The answer of What is the main property of a...

Question 5

What is the physical difference between an eclipsing binary system and a spectroscopic binary system?

Accepted Answer

The answer of What is the physical difference between an...

Question 6

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.

Question 7

A star classified as a K0III star is:

Accepted Answer

A) a giant that is cooler than the Sun 
B) a supergiant that is hotter than the Sun 
C) a main-sequence star that is hotter than the Sun 
D) a subgiant that is cooler than the Sun 
E) a dwarf that is hotter than the Sun

Question 8

Stars A and B appear equally bright,but star A is twice as far away from us as star B.Which of the following is true?

Accepted Answer

A) Star A is twice as luminous as star B. 
B) Star A is four times as luminous as star B. 
C) Star B is twice as luminous as star A. 
D) Star B is four times as luminous as star B. 
E) Star A and star B have the same luminosity because they have the same brightness.

Question 9

You observe a binary star system and find that star 1 has a velocity of 20 m/s while star 2 has a velocity of 40 m/s.What is the ratio of masses of the two stars (M₁/M₂)? If you find that the separation of the two stars is 0.5 AU and the orbital period is 70 days,then what are the individual masses of the two stars?

Accepted Answer

The answer of You observe a binary star system and...

Question 10

The habitable zone for the Sun covers the area that is between _________ from the Sun.

Accepted Answer

A) 0 to 0.8 AU 
B) 0.5 to 10 AU 
C) 1.2 to 4.2 AU 
D) 0.9 to 1.4 AU 
E) 0.2 to 10.2 AU

Question 11

Two main-sequence stars have the same temperature.If star A is four times brighter than star B,then:

Accepted Answer

A) star B is two times farther away than star A 
B) star B is four times farther away than star A 
C) star B is eight times farther away than star A 
D) star B and star A lie at the same distance from us 
E) it is impossible to determine their relative distances from the information given

Question 12

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

Accepted Answer

A) True 
 B)False

Question 13

With today's advanced technology,we can measure the parallax for any star inside the Milky Way.

Accepted Answer

A) True 
 B)False

Question 14

In a binary star system that contains stars with 2M☉ and 1M☉,the velocity of the 2M☉ star will be _________ times the velocity of the 1M☉ star.

Accepted Answer

A) 0.2 
B) 0.5 
C) 1 
D) 2 
E) 3

Question 15

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

The answer of Rigel is a star with an apparent...

Question 16

Star A emits its peak energy at a wavelength of 500 nm,and star B emits its peak energy at a wavelength of 750 nm.If both stars have the same radii,which star is hotter and by how much?

Accepted Answer

The answer of Star A emits its peak energy at...

Question 17

You observe a binary star system and find that star 1 has a velocity of 10 m/s while star 2 has a velocity of 35 m/s.What is the ratio of masses of the two stars (M₁/M₂)?

Accepted Answer

The answer of You observe a binary star system and...

Question 18

If star A has a temperature that is twice as hot as the Sun but has the same luminosity as the Sun,the diameter of star A must be _________ times the diameter of the Sun.

Accepted Answer

A) 16 
B) 4 
C) 2 
D) 1/2 
E) 1/4

Question 19

Which of the following properties are NOT useful in determining the masses of stars in a typical binary system?

Accepted Answer

A) The period of the orbits of the two stars is not useful. 
B) The average separation between the two stars is not useful. 
C) The radii of the two stars is not useful. 
D) The velocities of the two stars is not useful. 
E) All of the above are useful for determining the masses of stars in a binary.

Question 20

A parsec is a unit of time.

Accepted Answer

A) True 
 B)False

Exam 13: Taking the Measure of Stars

Stars X and Y are 5 AU apart from each other.Star X is four times as massive as star Y.The center of mass of this system is _ AU away from star X and _ AU away from star Y.

Star A is a red star.Star B is a blue star.You are able to determine that both stars are the same size.Which star is brighter?

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?

What is the main property of a main-sequence star that determines all its other properties?

What is the physical difference between an eclipsing binary system and a spectroscopic binary system?

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

A star classified as a K0III star is:

Stars A and B appear equally bright,but star A is twice as far away from us as star B.Which of the following is true?

The habitable zone for the Sun covers the area that is between _________ from the Sun.

Two main-sequence stars have the same temperature.If star A is four times brighter than star B,then:

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

With today's advanced technology,we can measure the parallax for any star inside the Milky Way.

In a binary star system that contains stars with 2M_☉ and 1M_☉,the velocity of the 2M_☉ star will be _________ times the velocity of the 1M_☉ star.

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?

Star A emits its peak energy at a wavelength of 500 nm,and star B emits its peak energy at a wavelength of 750 nm.If both stars have the same radii,which star is hotter and by how much?

You observe a binary star system and find that star 1 has a velocity of 10 m/s while star 2 has a velocity of 35 m/s.What is the ratio of masses of the two stars (M₁/M₂)?

If star A has a temperature that is twice as hot as the Sun but has the same luminosity as the Sun,the diameter of star A must be _________ times the diameter of the Sun.

Which of the following properties are NOT useful in determining the masses of stars in a typical binary system?

A parsec is a unit of time.

Exam 13: Taking the Measure of Stars

Stars X and Y are 5 AU apart from each other.Star X is four times as massive as star Y.The center of mass of this system is _________ AU away from star X and _________ AU away from star Y.

Star A is a red star.Star B is a blue star.You are able to determine that both stars are the same size.Which star is brighter?

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?

What is the main property of a main-sequence star that determines all its other properties?

What is the physical difference between an eclipsing binary system and a spectroscopic binary system?

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

A star classified as a K0III star is:

Stars A and B appear equally bright,but star A is twice as far away from us as star B.Which of the following is true?

The habitable zone for the Sun covers the area that is between _________ from the Sun.

Two main-sequence stars have the same temperature.If star A is four times brighter than star B,then:

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

With today's advanced technology,we can measure the parallax for any star inside the Milky Way.

In a binary star system that contains stars with 2M☉ and 1M☉,the velocity of the 2M☉ star will be _________ times the velocity of the 1M☉ star.

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?

Star A emits its peak energy at a wavelength of 500 nm,and star B emits its peak energy at a wavelength of 750 nm.If both stars have the same radii,which star is hotter and by how much?

You observe a binary star system and find that star 1 has a velocity of 10 m/s while star 2 has a velocity of 35 m/s.What is the ratio of masses of the two stars (M1/M2)?

If star A has a temperature that is twice as hot as the Sun but has the same luminosity as the Sun,the diameter of star A must be _________ times the diameter of the Sun.

Which of the following properties are NOT useful in determining the masses of stars in a typical binary system?

A parsec is a unit of time.

Stars X and Y are 5 AU apart from each other.Star X is four times as massive as star Y.The center of mass of this system is _ AU away from star X and _ AU away from star Y.

In a binary star system that contains stars with 2M_☉ and 1M_☉,the velocity of the 2M_☉ star will be _________ times the velocity of the 1M_☉ star.

You observe a binary star system and find that star 1 has a velocity of 10 m/s while star 2 has a velocity of 35 m/s.What is the ratio of masses of the two stars (M₁/M₂)?