Question 1

An H II region signals the presence of

Accepted Answer

A)  newly formed stars. 
B)  young stars. 
C)  O- and B-type stars. 
D)  All of the above 
A)  newly formed stars. 
B)  young stars. 
C)  O- and B-type stars. 
D)  All of the above

Question 2

Molecular clouds are best observed at __________ wavelengths.

Accepted Answer

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

Question 3

The entire process of star formation is really just an evolving balance between

Accepted Answer

A)  heat and rotation. 
B)  core temperature and surface temperature. 
C)  pressure and gravity. 
D)  radiation and heat. 
A)  heat and rotation. 
B)  core temperature and surface temperature. 
C)  pressure and gravity. 
D)  radiation and heat.

Question 4

A __________ is a failed star that shines primarily because of energy derived from its gravitational collapse.

Accepted Answer

A)  black hole 
B)  brown dwarf 
C)  protostar 
D)  T Tauri star 
A)  black hole 
B)  brown dwarf 
C)  protostar 
D)  T Tauri star

Question 5

Molecular cloud cores are places where you might find

Accepted Answer

A)  protostars. 
B)  Herbig-Haro objects. 
C)  carbon monoxide. 
D)  All of the above 
A)  protostars. 
B)  Herbig-Haro objects. 
C)  carbon monoxide. 
D)  All of the above

Question 6

What primarily makes it difficult to observe protostars?

Accepted Answer

A)  They occur in dusty regions. 
B)  They have low luminosities. 
C)  They do not shine at any wavelength until they become T Tauri stars. 
D)  The star formation process happens so quickly. 
A)  They occur in dusty regions. 
B)  They have low luminosities. 
C)  They do not shine at any wavelength until they become T Tauri stars. 
D)  The star formation process happens so quickly.

Question 7

Why do many stars form from a single molecular cloud?

Accepted Answer

Small density fluctuations in the parent

Question 8

Neutral hydrogen atoms are found only inside dense clouds where they are shielded from stellar radiation.

Accepted Answer

A) True 
 B)False

Question 9

If the temperature inside a protostar were to suddenly increase,the protostar would

Accepted Answer

A)  expand. 
B)  contract. 
C)  remain the same size. 
D)  explode. 
A)  expand. 
B)  contract. 
C)  remain the same size. 
D)  explode.

Question 10

Why can we see dust in the interstellar medium better at far-infrared wavelengths than we can at optical wavelengths?

Accepted Answer

Because the dust is cold at te

Question 11

Why does the surface temperature of a protostar remain nearly constant as its core contracts?

Accepted Answer

It remains nearly constant bec

Question 12

The coldest molecular clouds in our galaxy have temperatures of approximately 1,000 K.

Accepted Answer

A) True 
 B)False

Question 13

If you wanted to study regions where star formation is currently happening you could use

Accepted Answer

A)  Halpha emission to look for O and B stars. 
B)  a radio telescope to search for molecular cloud cores. 
C)  infrared emission to identify T Tauri stars. 
D)  All of the above 
A)  Halpha emission to look for O and B stars. 
B)  a radio telescope to search for molecular cloud cores. 
C)  infrared emission to identify T Tauri stars. 
D)  All of the above

Question 14

The dust in the interstellar medium comes primarily from stellar winds of main-sequence stars.

Accepted Answer

A) True 
 B)False

Question 15

What happens as a protostar contracts?

Accepted Answer

A)  Its density rises. 
B)  Its temperature rises. 
C)  Its pressure rises. 
D)  All of the above are true. 
A)  Its density rises. 
B)  Its temperature rises. 
C)  Its pressure rises. 
D)  All of the above are true.

Question 16

A surprising fact about a   protostar is that,even though nuclear reactions have not yet started in their cores,they are __________ than the Sun.

Accepted Answer

A)  hotter 
B)  rotating faster 
C)  denser 
D)  more luminous 
A)  hotter 
B)  rotating faster 
C)  denser 
D)  more luminous

Question 17

Some molecular clouds have so much internal pressure that it exceeds their self-gravity.What keeps them from expanding and dissipating?

Accepted Answer

The pressure of the external i

Question 18

Warm ionized gas in the interstellar medium appears __________ when imaged in the optical region of the electromagnetic spectrum.

Accepted Answer

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

Question 19

Brown dwarfs are considered failed stars because

Accepted Answer

A)  fusion never begins in their cores. 
B)  they never reach masses larger than 50 Jupiter masses. 
C)  convection never plays a role in their energy transport. 
D)  they primarily shine at infrared wavelengths. 
A)  fusion never begins in their cores. 
B)  they never reach masses larger than 50 Jupiter masses. 
C)  convection never plays a role in their energy transport. 
D)  they primarily shine at infrared wavelengths.

Question 20

Sitting in a 100°F hot tub feels much hotter than standing outside on a 100°F day.This analogy illustrates why

Accepted Answer

A)  interstellar dust is dark at optical wavelengths but bright in the infrared. 
B)  supernovae can heat their shells to such high temperatures. 
C)  an astronaut would feel cold in the 106 K intercloud gas. 
D)  the Solar System is immersed in a hot bubble of gas. 
A)  interstellar dust is dark at optical wavelengths but bright in the infrared. 
B)  supernovae can heat their shells to such high temperatures. 
C)  an astronaut would feel cold in the 106 K intercloud gas. 
D)  the Solar System is immersed in a hot bubble of gas.

Exam 15: Star Formation and the Interstellar Medium

An H II region signals the presence of

Molecular clouds are best observed at __________ wavelengths.

The entire process of star formation is really just an evolving balance between

A __________ is a failed star that shines primarily because of energy derived from its gravitational collapse.

Molecular cloud cores are places where you might find

What primarily makes it difficult to observe protostars?

Why do many stars form from a single molecular cloud?

Neutral hydrogen atoms are found only inside dense clouds where they are shielded from stellar radiation.

If the temperature inside a protostar were to suddenly increase,the protostar would

Why can we see dust in the interstellar medium better at far-infrared wavelengths than we can at optical wavelengths?

Why does the surface temperature of a protostar remain nearly constant as its core contracts?

The coldest molecular clouds in our galaxy have temperatures of approximately 1,000 K.

If you wanted to study regions where star formation is currently happening you could use

The dust in the interstellar medium comes primarily from stellar winds of main-sequence stars.

What happens as a protostar contracts?

A surprising fact about a protostar is that,even though nuclear reactions have not yet started in their cores,they are __________ than the Sun.

Some molecular clouds have so much internal pressure that it exceeds their self-gravity.What keeps them from expanding and dissipating?

Warm ionized gas in the interstellar medium appears __________ when imaged in the optical region of the electromagnetic spectrum.

Brown dwarfs are considered failed stars because

Sitting in a 100°F hot tub feels much hotter than standing outside on a 100°F day.This analogy illustrates why

Why Learn Astronomy

Patterns in the Skymotions of Earth

Gravity and Orbitsa Celestial Ballet

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 Liquidthe Giant Planets

Gravity Is More Than Keplers Laws

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

A Run-Of-The-Mill G-Type Starour Sun

Stars in the Slow Lanelow-Mass Stellar Evolution

Live Fast,die Younghigh-Mass Stellar Evolution

Our Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

The Origin of Structure

Life

Filters