Question 1

Star clusters are important to the study the stellar evolution because stars in a given cluster have the same

Accepted Answer

A)  temperature. 
B)  mass. 
C)  age. 
D)  luminosity. 
A)  temperature. 
B)  mass. 
C)  age. 
D)  luminosity.

Question 2

The hottest stars in the Orion Nebula ____________hydrogen gas and make it _____________.

Accepted Answer

A)  ionize,glow 
B)  neutralize,glow 
C)  ionize,swallow the star 
A)  ionize,glow 
B)  neutralize,glow 
C)  ionize,swallow the star

Question 3

Protons and neutrons are held together in the nucleus by

Accepted Answer

A)  the weak force. 
B)  the gravitational force. 
C)  the electrostatic force. 
D)  the strong force. 
E)  the opacity. 
A)  the weak force. 
B)  the gravitational force. 
C)  the electrostatic force. 
D)  the strong force. 
E)  the opacity.

Question 4

While on the main sequence a star's primary energy source comes from

Accepted Answer

A)  nuclear fusion. 
B)  nuclear fission. 
C)  gravitational potential energy. 
D)  magnetic fields. 
A)  nuclear fusion. 
B)  nuclear fission. 
C)  gravitational potential energy. 
D)  magnetic fields.

Question 5

Some young star clusters contain large numbers of T Tauri stars.

Accepted Answer

A) True 
 B)False

Question 6

Main sequence O stars have convective cores because

Accepted Answer

A)  they fuse hydrogen in the CNO cycle. 
B)  they fuse hydrogen in the proton-proton chain. 
C)  they contain mostly hydrogen. 
D)  they have very cool cores. 
E)  they have very large magnetic fields. 
A)  they fuse hydrogen in the CNO cycle. 
B)  they fuse hydrogen in the proton-proton chain. 
C)  they contain mostly hydrogen. 
D)  they have very cool cores. 
E)  they have very large magnetic fields.

Question 7

____ are small luminous nebulae excited by nearby young stars.

Accepted Answer

A)  T Tauri stars 
B)  Herbig-Haro objects 
C)  O associations 
D)  WIMPS 
E)  Giant molecular clouds 
A)  T Tauri stars 
B)  Herbig-Haro objects 
C)  O associations 
D)  WIMPS 
E)  Giant molecular clouds

Question 8

The central cores of massive main sequence stars

Accepted Answer

A)  produce energy by the proton-proton chain. 
B)  have a very low opacity. 
C)  transmit energy outward by convection. 
D)  burn their nuclear fuels more slowly than low mass main sequence stars. 
E)  have lower temperatures than the central cores of low mass main sequence stars. 
A)  produce energy by the proton-proton chain. 
B)  have a very low opacity. 
C)  transmit energy outward by convection. 
D)  burn their nuclear fuels more slowly than low mass main sequence stars. 
E)  have lower temperatures than the central cores of low mass main sequence stars.

Question 9

Most stars generate their energy by the thermonuclear fusion of ____________________ to form ____________________.

Accepted Answer

The answer of Most stars generate their energy by the...

Question 10

Pre-main sequence stars are above and to the right of the main sequence.

Accepted Answer

A) True 
 B)False

Question 11

The Orion region contains young main sequence stars and an emission nebula,but the original molecular cloud they formed out of has been dispersed.

Accepted Answer

A) True 
 B)False

Question 12

The Great Nebula in Orion

Accepted Answer

A)  is a Herbig-Haro object. 
B)  is a reflection nebula. 
C)  is an emission nebula. 
D)  contains only young low mass stars. 
E)  is believed to be about 5 billion years old. 
A)  is a Herbig-Haro object. 
B)  is a reflection nebula. 
C)  is an emission nebula. 
D)  contains only young low mass stars. 
E)  is believed to be about 5 billion years old.

Question 13

The sun has a core in which energy travels outward primarily by radiation.

Accepted Answer

A) True 
 B)False

Question 14

Ionization from the ____________________ star in the Orion nebula makes it ____________________ brightly.

Accepted Answer

The answer of Ionization from the ____________________ star in the...

Question 15

The BN object in the Orion molecular cloud is believed to be

Accepted Answer

A)  a star cluster hidden in dust clouds. 
B)  a forming star nearing the main sequence. 
C)  a low-mass star fusing hydrogen in its interior. 
D)  a low-density gas cloud heated by a shock wave. 
E)  a black hole radiating large amounts of x-ray radiation. 
A)  a star cluster hidden in dust clouds. 
B)  a forming star nearing the main sequence. 
C)  a low-mass star fusing hydrogen in its interior. 
D)  a low-density gas cloud heated by a shock wave. 
E)  a black hole radiating large amounts of x-ray radiation.

Question 16

Convection is important in stars because it

Accepted Answer

A)  increases the temperature of the star. 
B)  mixes the gases of the star. 
C)  transports energy outward in the star. 
D)  carries the neutrinos to the surface of the star where they can escape. 
E)  b and c 
A)  increases the temperature of the star. 
B)  mixes the gases of the star. 
C)  transports energy outward in the star. 
D)  carries the neutrinos to the surface of the star where they can escape. 
E)  b and c

Question 17

The central cores of which type of star is the lowest temperature?

Accepted Answer

A)  protostars. 
B)  massive main sequence stars 
C)  low mass main sequence stars. 
A)  protostars. 
B)  massive main sequence stars 
C)  low mass main sequence stars.

Question 18

A(n)____________________ is a cool,dense cloud of dust and gas that is undergoing gravitational contraction.

Accepted Answer

The answer of A(n)____________________ is a cool,dense cloud of dust...

Question 19

In the collapse of a protostar ____________________ energy is converted to ____________________ energy.

Accepted Answer

The answer of In the collapse of a protostar ____________________...

Question 20

The free-fall contraction of a molecular cloud

Accepted Answer

A)  can be initiated by shock waves from supernovae. 
B)  can be initiated by nearby spectral type G stars. 
C)  can be initiated by the rotation of the cloud. 
D)  causes the cloud to become transparent to ultraviolet radiation. 
E)  causes the particles in the cloud to decrease the speed with which they move. 
A)  can be initiated by shock waves from supernovae. 
B)  can be initiated by nearby spectral type G stars. 
C)  can be initiated by the rotation of the cloud. 
D)  causes the cloud to become transparent to ultraviolet radiation. 
E)  causes the particles in the cloud to decrease the speed with which they move.

Exam 11: The Formation and Structure of Stars

Star clusters are important to the study the stellar evolution because stars in a given cluster have the same

The hottest stars in the Orion Nebula ____________hydrogen gas and make it _____________.

Protons and neutrons are held together in the nucleus by

While on the main sequence a star's primary energy source comes from

Some young star clusters contain large numbers of T Tauri stars.

Main sequence O stars have convective cores because

____ are small luminous nebulae excited by nearby young stars.

The central cores of massive main sequence stars

Most stars generate their energy by the thermonuclear fusion of ____________________ to form ____________________.

Pre-main sequence stars are above and to the right of the main sequence.

The Orion region contains young main sequence stars and an emission nebula,but the original molecular cloud they formed out of has been dispersed.

The Great Nebula in Orion

The sun has a core in which energy travels outward primarily by radiation.

Ionization from the ____________________ star in the Orion nebula makes it ____________________ brightly.

The BN object in the Orion molecular cloud is believed to be

Convection is important in stars because it

The central cores of which type of star is the lowest temperature?

A(n)____________________ is a cool,dense cloud of dust and gas that is undergoing gravitational contraction.

In the collapse of a protostar ____________________ energy is converted to ____________________ energy.

The free-fall contraction of a molecular cloud

Here and Now

A Users Guide to the Sky

Cycles of the Moon

The Origin of Modern Astronomy

Gravity

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Interstellar Medium

Stellar Evolution

The Deaths of Stars

Neutron Stars and Black Holes

The Milky Way Galaxy

Galaxies

Active Galaxies and Supermassive Black Holes

Modern Cosmology

The Origin of the Solar System

Earth: the Standard of Comparative Planetology

The Moon and Mercury: Comparing Airless Worlds

Venus and Mars

Jupiter and Saturn

Uranus,neptune,and the Kuiper Belt

Meteorites,asteroids,and Comets

Astrobiology: Life on Other Worlds

Filters

The hottest stars in the Orion Nebula hydrogen gas and make it _.

Most stars generate their energy by the thermonuclear fusion of to form .

Ionization from the star in the Orion nebula makes it brightly.

In the collapse of a protostar energy is converted to energy.