Question 1

Which molecule is likely to be the MOST common in interstellar space?

Accepted Answer

A)  OH, hydroxyl 
B)  H₂, molecular hydrogen 
C)  CO, carbon monoxide 
D)  H₂O, water 
A)  OH, hydroxyl 
B)  H₂, molecular hydrogen 
C)  CO, carbon monoxide 
D)  H₂O, water

Question 2

The study of stars in clusters has especially helped astronomers to understand:

Accepted Answer

A)  stellar evolution, the development of stars with time. 
B)  the mechanism of mass loss in stars. 
C)  the reason for differences in surface temperatures of stars. 
D)  the action of nuclear fusion in stars. 
A)  stellar evolution, the development of stars with time. 
B)  the mechanism of mass loss in stars. 
C)  the reason for differences in surface temperatures of stars. 
D)  the action of nuclear fusion in stars.

Question 3

How does an interstellar cloud collapse to become a star?

Accepted Answer

A)  The innermost part collapses first; then the outer part is drawn in by the gravity of the inner part. 
B)  The collapse is turbulent and chaotic, with no overall pattern. 
C)  The outer, less dense part falls in first and its weight accelerates the collapse of the inner part. 
D)  All parts of the cloud accelerate inward more or less smoothly and evenly. 
A)  The innermost part collapses first; then the outer part is drawn in by the gravity of the inner part. 
B)  The collapse is turbulent and chaotic, with no overall pattern. 
C)  The outer, less dense part falls in first and its weight accelerates the collapse of the inner part. 
D)  All parts of the cloud accelerate inward more or less smoothly and evenly.

Question 4

How long does a star of three times the Sun's mass live compared with the lifetime of the Sun? (See Table 11-2,Comins,Discovering the Essential Universe,6th ed.)

Accepted Answer

A)  A star of three times the Sun's mass lives about 1/3 as long as the Sun. 
B)  A star of three times the Sun's mass lives about 1/20 as long as the Sun. 
C)  A star of three times the Sun's mass lives about three times as long as the Sun. 
D)  A star of three times the Sun's mass lives about 1/500 as long as the Sun. 
A)  A star of three times the Sun's mass lives about 1/3 as long as the Sun. 
B)  A star of three times the Sun's mass lives about 1/20 as long as the Sun. 
C)  A star of three times the Sun's mass lives about three times as long as the Sun. 
D)  A star of three times the Sun's mass lives about 1/500 as long as the Sun.

Question 5

The characteristics of an open cluster of stars are:

Accepted Answer

A)  a few hundred members, often very young and still embedded in the gas and dust from which they were formed. 
B)  hundreds of thousands of members, all very old, surrounded by very little interstellar gas and dust. 
C)  a few dozen members, the remnant of a globular cluster of stars from which most of the members have escaped. 
D)  many thousands of members of different ages. 
A)  a few hundred members, often very young and still embedded in the gas and dust from which they were formed. 
B)  hundreds of thousands of members, all very old, surrounded by very little interstellar gas and dust. 
C)  a few dozen members, the remnant of a globular cluster of stars from which most of the members have escaped. 
D)  many thousands of members of different ages.

Question 6

Protostars,when they first form from the interstellar medium,are usually:

Accepted Answer

A)  very bright in ultraviolet light due to numerous flares that are hotter and brighter than solar flares. 
B)  detected by emission lines in their visible spectra, emitted by gas being blown off their surfaces into space. 
C)  easily detected because their light ionizes the surrounding interstellar gas, or reflection nebulae. 
D)  hidden from sight by dust clouds that emit infrared radiation. 
A)  very bright in ultraviolet light due to numerous flares that are hotter and brighter than solar flares. 
B)  detected by emission lines in their visible spectra, emitted by gas being blown off their surfaces into space. 
C)  easily detected because their light ionizes the surrounding interstellar gas, or reflection nebulae. 
D)  hidden from sight by dust clouds that emit infrared radiation.

Question 7

What is the typical temperature inside the dense core of a giant molecular cloud that is collapsing to form a star?

Accepted Answer

A)  less than 1 K 
B)  10 K 
C)  1000 K 
D)  100 K 
A)  less than 1 K 
B)  10 K 
C)  1000 K 
D)  100 K

Question 8

What is the lowest mass an object can have and still be a star?

Accepted Answer

A)  0.002 solar mass (twice Jupiter's mass) 
B)  0.80 solar mass 
C)  0.08 solar mass 
D)  0.02 solar mass 
A)  0.002 solar mass (twice Jupiter's mass) 
B)  0.80 solar mass 
C)  0.08 solar mass 
D)  0.02 solar mass

Question 9

What is happening in a star that is on the main sequence on the Hertzsprung-Russell diagram?

Accepted Answer

A)  The star is generating energy by helium fusion, having stopped hydrogen "burning." 
B)  The star is slowly shrinking as it slides down the main sequence from top left to bottom right across the H-R diagram. 
C)  Stars that have reached the main sequence have ceased nuclear "burning" and are simply cooling down by emitting radiation. 
D)  The star is generating internal energy by hydrogen fusion. 
A)  The star is generating energy by helium fusion, having stopped hydrogen "burning." 
B)  The star is slowly shrinking as it slides down the main sequence from top left to bottom right across the H-R diagram. 
C)  Stars that have reached the main sequence have ceased nuclear "burning" and are simply cooling down by emitting radiation. 
D)  The star is generating internal energy by hydrogen fusion.

Question 10

The present estimate of the age of the universe is about 14 billion years.How long will a half-solar-mass star spend on the main sequence,compared with the present age of the universe? (See Table 11-2,Comins,Discovering the Essential Universe,6th ed.)

Accepted Answer

A)  about three times the age of the universe 
B)  more than ten times the age of the universe 
C)  less than 1/10 of the age of the universe 
D)  about 1/2 of the age of the universe 
A)  about three times the age of the universe 
B)  more than ten times the age of the universe 
C)  less than 1/10 of the age of the universe 
D)  about 1/2 of the age of the universe

Question 11

Where in the universe would you look for a protostar?

Accepted Answer

A)  near black holes 
B)  in dense dust and gas clouds 
C)  in the empty space between galaxies 
D)  in globular clusters of stars 
A)  near black holes 
B)  in dense dust and gas clouds 
C)  in the empty space between galaxies 
D)  in globular clusters of stars

Question 12

What is a typical size for a giant molecular cloud?

Accepted Answer

A)  100 ly across 
B)  1000 ly across 
C)  anything up to about 1 ly across 
D)  10 ly across 
A)  100 ly across 
B)  1000 ly across 
C)  anything up to about 1 ly across 
D)  10 ly across

Question 13

How long does it take for a 1-solar-mass star to pass through the pre-main-sequence phase?

Accepted Answer

A)  10 million years 
B)  10,000 years 
C)  10 billion years 
D)  100,000 years 
A)  10 million years 
B)  10,000 years 
C)  10 billion years 
D)  100,000 years

Question 14

How large will the Sun be as a red giant?

Accepted Answer

A)  about 1 AU radius (out to Earth's orbit) 
B)  about 1/10 AU radius (1/4 of Mercury's orbit) 
C)  about 1.5 AU radius (out to Mars' orbit) 
D)  about 1/2 AU radius (beyond Mercury's orbit) 
A)  about 1 AU radius (out to Earth's orbit) 
B)  about 1/10 AU radius (1/4 of Mercury's orbit) 
C)  about 1.5 AU radius (out to Mars' orbit) 
D)  about 1/2 AU radius (beyond Mercury's orbit)

Question 15

Protostars are slowly;

Accepted Answer

A)  expanding at the surface while the core contracts. 
B)  contracting and heating up. 
C)  heating up and expanding. 
D)  contracting and cooling. 
A)  expanding at the surface while the core contracts. 
B)  contracting and heating up. 
C)  heating up and expanding. 
D)  contracting and cooling.

Question 16

It is now believed that MOST stars are:

Accepted Answer

A)  isolated and not in binary systems. 
B)  in binary systems. 
C)  more massive than the Sun. 
D)  red giants. 
A)  isolated and not in binary systems. 
B)  in binary systems. 
C)  more massive than the Sun. 
D)  red giants.

Question 17

What is the characteristic color of a reflection nebula?

Accepted Answer

A)  red 
B)  yellow 
C)  green 
D)  blue 
A)  red 
B)  yellow 
C)  green 
D)  blue

Question 18

If one were to look for a protostar in its early stages,one would observe in which wavelength region?

Accepted Answer

A)  ultraviolet 
B)  visible 
C)  infrared 
D)  radio 
A)  ultraviolet 
B)  visible 
C)  infrared 
D)  radio

Question 19

Over which stage of stellar evolution does the radius of a star remain approximately constant?

Accepted Answer

A)  the main-sequence phase 
B)  the asymptotic giant branch phase 
C)  the red giant phase 
D)  birth and initial formation 
A)  the main-sequence phase 
B)  the asymptotic giant branch phase 
C)  the red giant phase 
D)  birth and initial formation

Question 20

The final stage in the evolution of a red dwarf star is:

Accepted Answer

A)  a star of pure helium which generates energy by fusing helium into carbon. 
B)  a star of pure helium which no longer generates energy by nuclear fusion. 
C)  a red giant. 
D)  unknown because no red dwarf has ever evolved off the main sequence. 
A)  a star of pure helium which generates energy by fusing helium into carbon. 
B)  a star of pure helium which no longer generates energy by nuclear fusion. 
C)  a red giant. 
D)  unknown because no red dwarf has ever evolved off the main sequence.

Which molecule is likely to be the MOST common in interstellar space?

The study of stars in clusters has especially helped astronomers to understand:

How does an interstellar cloud collapse to become a star?

How long does a star of three times the Sun's mass live compared with the lifetime of the Sun? (See Table 11-2,Comins,Discovering the Essential Universe,6th ed.)

The characteristics of an open cluster of stars are:

Protostars,when they first form from the interstellar medium,are usually:

What is the typical temperature inside the dense core of a giant molecular cloud that is collapsing to form a star?

What is the lowest mass an object can have and still be a star?

What is happening in a star that is on the main sequence on the Hertzsprung-Russell diagram?

The present estimate of the age of the universe is about 14 billion years.How long will a half-solar-mass star spend on the main sequence,compared with the present age of the universe? (See Table 11-2,Comins,Discovering the Essential Universe,6th ed.)

Where in the universe would you look for a protostar?

What is a typical size for a giant molecular cloud?

How long does it take for a 1-solar-mass star to pass through the pre-main-sequence phase?

How large will the Sun be as a red giant?

Protostars are slowly;

It is now believed that MOST stars are:

What is the characteristic color of a reflection nebula?

If one were to look for a protostar in its early stages,one would observe in which wavelength region?

Over which stage of stellar evolution does the radius of a star remain approximately constant?

The final stage in the evolution of a red dwarf star 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

Characterizing Stars

The Deaths and Remnants of Stars

The Galaxies

Cosmology

Astrobiology

Filters

Exam 11: The Lives of the Stars From Birth Through Middle Age

Which molecule is likely to be the MOST common in interstellar space?

The study of stars in clusters has especially helped astronomers to understand:

How does an interstellar cloud collapse to become a star?

How long does a star of three times the Sun's mass live compared with the lifetime of the Sun? (See Table 11-2,Comins,Discovering the Essential Universe,6th ed.)

The characteristics of an open cluster of stars are:

Protostars,when they first form from the interstellar medium,are usually:

What is the typical temperature inside the dense core of a giant molecular cloud that is collapsing to form a star?

What is the lowest mass an object can have and still be a star?

What is happening in a star that is on the main sequence on the Hertzsprung-Russell diagram?

The present estimate of the age of the universe is about 14 billion years.How long will a half-solar-mass star spend on the main sequence,compared with the present age of the universe? (See Table 11-2,Comins,Discovering the Essential Universe,6th ed.)

Where in the universe would you look for a protostar?

What is a typical size for a giant molecular cloud?

How long does it take for a 1-solar-mass star to pass through the pre-main-sequence phase?

How large will the Sun be as a red giant?

Protostars are slowly;

It is now believed that MOST stars are:

What is the characteristic color of a reflection nebula?

If one were to look for a protostar in its early stages,one would observe in which wavelength region?

Over which stage of stellar evolution does the radius of a star remain approximately constant?

The final stage in the evolution of a red dwarf star 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

Characterizing Stars

The Deaths and Remnants of Stars

The Galaxies

Cosmology

Astrobiology

Filters