Chapter 18 Homework 15 The Bizzare Stellar Graveyard Flashcards Preview

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Flashcards in Chapter 18 Homework 15 The Bizzare Stellar Graveyard Deck (54)
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1

A white dwarf is _________.

what most stars become when they die
an early stage of a neutron star
a precursor to a black hole
a brown dwarf that has exhausted its fuel for nuclear fusion

what most stars become when they die

2

A typical white dwarf is _________.

as massive as the Sun but only about as large in size as Jupiter
about the same size and mass as the Sun but much hotter
as massive as the Sun but only about as large in size as Earth
as large in diameter as the Sun but only about as massive as Earth

as massive as the Sun but only about as large in size as Earth

3

The maximum mass of a white dwarf is _________.

about 1.4 times the mass of our Sun
limitless; there is no theoretical limit to the maximum mass of a white dwarf
about 3 times the mass of our Sun
about the mass of our Sun

about 1.4 times the mass of our Sun

4

A neutron star is _________.

an object that will ultimately become a black hole
the remains of a star that died by expelling its outer layers in a planetary nebula
a star made mostly of elements with high atomic mass numbers, so that they have lots of neutrons
the remains of a star that died in a massive star supernova (if no black hole was created)

the remains of a star that died in a massive star supernova (if no black hole was created)

5

A typical neutron star is more massive than our Sun and about the size (radius) of _________.

a small asteroid (10 km in diameter)
Jupiter
Earth
the Moon

a small asteroid (10 km in diameter)

6

If you had something the size of a sugar cube that was made of neutron star matter, it would weigh _________.

as much as the entire Earth
about as much as a large mountain
about 50 pounds
about as much as a truck

about as much as a large mountain

7

Pulsars are thought to be _________.

unstable high-mass stars
accreting white dwarfs
accreting black holes
rapidly rotating neutron stars

rapidly rotating neutron stars

8

What is the basic definition of a black hole?

a dead star that has faded from view
any object made from dark matter
a compact mass that emits no visible light
an object with gravity so strong that not even light can escape

an object with gravity so strong that not even light can escape

9

What do we mean by the event horizon of a black hole?

It is the place where X rays are emitted from black holes.
It is the very center of the black hole.
It is the point beyond which neither light nor anything else can escape.
It is the distance from the black hole at which stable orbits are possible.

It is the point beyond which neither light nor anything else can escape.

10

What do we mean by the singularity of a black hole?

It is the center of the black hole, a place of infinite density where the known laws of physics cannot describe the conditions.
The term is intended to emphasize the fact that an object can become a black hole only once, and a black hole cannot evolve into anything else.
It is the "point of no return" of the black hole; anything closer than this point will not be able to escape the gravitational force of the black hole.
It is the edge of the black hole, where one could leave the observable universe.

It is the center of the black hole, a place of infinite density where the known laws of physics cannot describe the conditions.

11

The radius of a white dwarf is determined by a balance between the inward force of gravity and the outward push of _________.

electron degeneracy pressure

12

A(n) _______ occurs when hydrogen fusion ignites on the surface of a white dwarf in a binary system.

nova

13

A(n) ________ occurs when fusion creates iron in the core of a star.

massive star supernova

14

A white dwarf in a close binary system will explode as a supernova if it gains enough mass to exceed the _____________

white dwarf limit (1.4 solar masses).

15

A(n) __________ consists of hot, swirling gas captured by a white dwarf ( or neutron star or black hole ) from a binary companion star.

accretion disk

16

A(n) ________ can occur only in a binary system, and all such events are thought to have the same luminosity.

white dwarf supernova

17

Listed following are several astronomical objects. Rank these objects based on their diameter, from largest to smallest. (Note that the neutron star and black hole in this example have the same mass to make your comparison easier, but we generally expect black holes to have greater masses than neutron stars.)

main-sequence star of spectral type a
jupiter
a one solar mass white dwarf
the moon
a two solar mass neutron star
event horizon of a two solar mass black hole

main-sequence star of spectral type a
jupiter
a one solar mass white dwarf
the moon
a two solar mass neutron star
event horizon of a two solar mass black hole

18

Listed following are several astronomical objects. Rank these objects based on their mass, from largest to smallest. (Be sure to notice that the main-sequence star here has a different spectral type from the one in Part A.)

a typical black hole (formed in supernova)
a typical neutron star
a one solar mass white dwarf
main-sequence star of spectral type m
jupiter
the moon

a typical black hole (formed in supernova)
a typical neutron star
a one solar mass white dwarf
main-sequence star of spectral type m
jupiter
the moon

19

Listed following are several astronomical objects. Rank these objects based on their density, from highest to lowest.

singularity of a black hole
a typical neutron star
a one solar mass white dwarf
a main-sequence star

singularity of a black hole
a typical neutron star
a one solar mass white dwarf
a main-sequence star

20

Listed following are distinguishing characteristics of different end states of stars. Match these to the appropriate consequence of stellar death. White Dwarf

has a mass no greater than 1.4 Msun
supported by electron degeneracy pressure
in a binary system, it can explode as a supernova,
typically about the size (diameter) of Earth
sometimes appears as a pulsar
usually has a very strong magnetic field
view from afar, time stops at its event horizon
size defined by its schwarzschild radius

has a mass no greater than 1.4 Msun
supported by electron degeneracy pressure
in a binary system, it can explode as a supernova,
typically about the size (diameter) of Earth

21

Listed following are distinguishing characteristics of different end states of stars. Match these to the appropriate consequence of stellar death. Neutron Star

has a mass no greater than 1.4 Msun
supported by electron degeneracy pressure
in a binary system, it can explode as a supernova,
typically about the size (diameter) of Earth
sometimes appears as a pulsar
usually has a very strong magnetic field
view from afar, time stops at its event horizon
size defined by its schwarzschild radius

sometimes appears as a pulsar
usually has a very strong magnetic field

22

Listed following are distinguishing characteristics of different end states of stars. Match these to the appropriate consequence of stellar death. Black hole

has a mass no greater than 1.4 Msun
supported by electron degeneracy pressure
in a binary system, it can explode as a supernova,
typically about the size (diameter) of Earth
sometimes appears as a pulsar
usually has a very strong magnetic field
view from afar, time stops at its event horizon
size defined by its schwarzschild radius

view from afar, time stops at its event horizon
size defined by its schwarzschild radius

23

The following items describe observational characteristics that could indicate that an object is either a white dwarf or a neutron star. Match each characteristic to the correct object.
White dwarf:

may be in a binary system that undergoes nova explosions.
may be surrounded by a planetary nebula.
emits most strongly in visible and ultraviolet.
may be surrounded by a supernova remnant.
may repeatedly dim and brighten more than once per second.
can have a mass of 1.5 solar masses.
may be in a binary system that undergoes x-ray bursts.

may be in a binary system that undergoes nova explosions.
may be surrounded by a planetary nebula.
emits most strongly in visible and ultraviolet.

24

The following items describe observational characteristics that could indicate that an object is either a white dwarf or a neutron star. Match each characteristic to the correct object.
Neutron star:

may be in a binary system that undergoes nova explosions.
may be surrounded by a planetary nebula.
emits most strongly in visible and ultraviolet.
may be surrounded by a supernova remnant.
may repeatedly dim and brighten more than once per second.
can have a mass of 1.5 solar masses.
may be in a binary system that undergoes x-ray bursts.

may be surrounded by a supernova remnant.
may repeatedly dim and brighten more than once per second.
can have a mass of 1.5 solar masses.
may be in a binary system that undergoes x-ray bursts.

25

The following items describe observational characteristics that may indicate that an object is either a neutron star or a black hole. Match each characteristic to the correct object; if the characteristic could apply to both types of object, choose the bin labeled "Both neutron stars and black holes."
Neutron star only:

may emit rapid pulses of radio waves.
may be in binary system that undergoes x-ray bursts.
is detectable only if it is accreting gas from other objects.
can have a mass of 10 solar masses
may be located in a x-ray binary.
may be surrounded by a supernova remnant.

may emit rapid pulses of radio waves.
may be in binary system that undergoes x-ray bursts.

26

The following items describe observational characteristics that may indicate that an object is either a neutron star or a black hole. Match each characteristic to the correct object; if the characteristic could apply to both types of object, choose the bin labeled "Both neutron stars and black holes."
Black hole only:

may emit rapid pulses of radio waves.
may be in binary system that undergoes x-ray bursts.
is detectable only if it is accreting gas from other objects.
can have a mass of 10 solar masses
may be located in a x-ray binary.
may be surrounded by a supernova remnant.

is detectable only if it is accreting gas from other objects.
can have a mass of 10 solar masses

27

The following items describe observational characteristics that may indicate that an object is either a neutron star or a black hole. Match each characteristic to the correct object; if the characteristic could apply to both types of object, choose the bin labeled "Both neutron stars and black holes."
Both Neutron star and black holes:

may emit rapid pulses of radio waves.
may be in binary system that undergoes x-ray bursts.
is detectable only if it is accreting gas from other objects.
can have a mass of 10 solar masses
may be located in a x-ray binary.
may be surrounded by a supernova remnant.

may be located in a x-ray binary.
may be surrounded by a supernova remnant

28

The Chandra X-Ray Observatory has detected X rays from a star system that contains a main-sequence star of spectral type B6. The X-ray emission is strong and fairly steady, and no sudden bursts have been observed. Which of the following statements are reasonable conclusions about this system?
Check all that apply.

Some time in the next few decades, this system will undergo a nova explosion.
The main-sequence star orbits either a white dwarf or a neutron star.
Gas from the main-sequence star makes an accretion disk around another object.
The main-sequence star orbits either a neutron star or a black hole.
The main-sequence star must orbit a neutron star.
The main-sequence star must orbit a white dwarf.
The main-sequence star must orbit a black hole.
The main-sequence star is emitting X rays.

Gas from the main-sequence star makes an accretion disk around another object.
The main-sequence star orbits either a neutron star or a black hole.

29

What is the key observation needed to determine whether the compact object in Part C is a neutron star or a black hole?

Study the X-ray emission to determine the temperature of the gas in the accretion disk.
Measure Doppler shifts in the spectrum of the main-sequence star so that you can determine the mass of the compact object.
Obtain high-resolution images of the compact object, so that you can determine whether it emits any light.

Measure Doppler shifts in the spectrum of the main-sequence star so that you can determine the mass of the compact object.

30

What do we mean by dimension in the context of relativity?

the letter used to represent length mathematically
the number of sides that we can see when we look at an object
the number of independent directions in which movement is possible
the size of an object

the number of independent directions in which movement is possible