Astronomy 3

Front 1

What makes the subject of star formation so difficult and complex?

Back 1

Stars live too long to be observed from birth to death

Front 2

Which statement about the stages of starbirth is false

Back 2

Nuclear reactions begin in the core by stage 4

Front 3

In the collapsing cloud fragment stage (stage 2) of star formation, the size of the cloud fragment is about

Back 3

100 times the size of the solar systen

Front 4

Stage 4 of star formation is when the object can exhibit violent surface activity producing extremely strong protostellar wind. this phase is also called the

Back 4

T-Tauri Phase

Front 5

What is the critical temperature at which hydrogen can fuse into helium in the star's core?

Back 5

ten million K

Front 6

If the initial interstellar cloud in star formation has a mass sufficient to form hundreds of stars, how does a single star form from it?

Back 6

the cloud fragments into smaller clouds and forms many stars at once

Front 7

At what stage of evolution do T-Tauri stars occur?

Back 7

When a protostar is on the verge of becoming a main sequence star.

Front 8

A star spends most of its life:

Back 8

as a main sequence star.

Front 9

The order of evolutionary stages of a star like the Sun would be Main Sequence, giant, planetary nebula, and finally:

Back 9

A white dwarf

Front 10

What is a typical age for a globular cluster?

Back 10

12 billion years

Front 11

What spectral type of star that is still around (not in a binary system) formed most recently?

Back 11

O

Front 12

Just as a low-mass main sequence star runs out of fuel in its core, it actually becomes brighter. How is this possible?

Back 12

The core contracts, raising the core temperature and increasing the size of the shell of hydrogen burning.

Front 13

Which of these will the Sun probably become in the very distant future?

Back 13

planetary nebula

Front 14

What characteristic of a star cluster is used to determine its age?
A) the ratio of main sequence to white dwarfs stars
B) the main sequence turnoff
C) the number of red giants
D) the faintest stars seen in the cluster
E) the total number of stars in the cluster

Back 14

B) the main sequence turnoff

Front 15

A surface explosion on a white dwarf, caused by falling matter from the atmosphere of its binary companion, creates what kind of object?
A) type II supernova
B) gamma ray burstar
C) nova
D) hypernova
E) type I supernova

Back 15

C) nova

Front 16

What evidence is there that supernovae really have occurred?
A) supernova remnants
B) Crab Nebula
C) All of the answer choices are correct
D) observations of the actual explosions
E) existence of heavy radioactive elements in nature

Back 16

C) All of the answer choices are correct

Front 17

Which of these is the likely progenitor of a type I supernova?
A) a mass-transfer binary, with the white dwarf already at 1.3 solar masses
B) a contact binary, with the neutron star at 2.3 solar masses
C) an evolved blue supergiant that is about to experience the helium flash
D) a helium-neon white dwarf
E) an evolved red giant which is just starting to make silicon in its core

Back 17

A) a mass-transfer binary, with the white dwarf already at 1.3 solar masses

Front 18

Most of the energy of the supernova is carried outward via a flood of:
A) protons.
B) helium nuclei.
C) neutrinos.
D) positrons.
E) gamma rays.

Back 18

C) neutrinos.

Front 19

The making of abundant iron nuclei is typical of:
A) planetary nebula ejection.
B) all novae.
C) the helium flash.
D) type I supernovae.
E) type II supernovae.

Back 19

E) type II supernovae.

Front 20

What is stellar nucleosynthesis?
A) The formation of stars from a nucleus of contracting material.
B) The formation of planetary nebulae by red giants.
C) The formation of heavier elements inside stars.
D) The formation of white dwarfs, neutron stars, and black holes from stars.
E) The process by which stars form interstellar dust.

Back 20

C) The formation of heavier elements inside stars.

Front 21

An iron core cannot support a star because:
A) iron is in the form of a gas, not a solid, in the center of a star.
B) iron supplies too much pressure.
C) iron has poor nuclear binding energy.
D) iron cannot fuse with other nuclei to produce energy.
E) iron is the heaviest element, and sinks upon differentiation.

Back 21

D) iron cannot fuse with other nuclei to produce energy.

Front 22

The supernova of 1054 AD produced:
A) a pulsar with a period of 33 milliseconds, visible optically.
B) a remnant still visible to the naked eye, the Crab Nebula, M-1.
C) the most famous black hole.
D) the closest known neutron star to our Sun.
E) no remaining visible trace, as it was a type I supernova.

Back 22

A) a pulsar with a period of 33 milliseconds, visible optically.

Front 23

X-ray bursters occur in binary star systems. The two types of stars that must be present to make up such an object are:
A) a white dwarf and a main sequence star.
B) two neutron stars in a mass transfer binary.
C) a main sequence or giant star and a neutron star in a mass transfer binary.
D) a contact binary system of two red giants.
E) a white dwarf and a neutron star.

Back 23

C) a main sequence or giant star and a neutron star in a mass transfer binary.

Front 24

A proposed explanation for gamma-ray bursters is
A) All of the answer choices are possible explanations.
B) coalescence of a neutron star binary.
C) collisions between two white dwarfs
D) hypernova-making black holes and bi-polar jets.

Back 24

A) All of the answer choices are possible explanations.

Front 25

Neutron stars have
A) periods of days or weeks.
B) weak or non-existent magnetic fields.
C) very strong bi-polar magnetic fields.
D) no relation to pulsars.
E) monopolar fields that switch polarity every rotation.

Back 25

C) very strong bi-polar magnetic fields.

Front 26

Which of the following can actually escape from inside a black hole's event horizon?
A) electrons
B) neutrinos
C) Nothing can escape from inside a black hole's event horizon.
D) gravitons
E) very high energy gamma-rays

Back 26

C) Nothing can escape from inside a black hole's event horizon.

Front 27

Almost half of all known millisecond pulsars are found in what type of object?
A) open clusters
B) globular clusters
C) emission nebulae
D) supernova remnants
E) giant molecular clouds

Back 27

B) globular clusters

Front 28

What is the name of the most famous black hole candidate?
A) Centaurus A
B) Cygnus X-1
C) Betelguese
D) Scorpio X-1
E) Sagittarius A

Back 28

B) Cygnus X-1

Front 29

What makes the subject of star formation so difficult and complex?
A) It is so slow that no visible proof of it exists.
B) Stars live too long to be observed from birth to death.
C) Shock waves disrupt the orderly evolution of stars.
D) Star formation is too expensive to study in detail.
E) Clouds, fragments, protostars, stars, and nebulae all interact and influence each other.

Back 29

B) Stars live too long to be observed from birth to death.

Front 30

Which statement about the stages of starbirth is false?
A) By stage 3, the star has formed a photosphere.
B) The T-Tauri wind is prevalent in stage 5.
C) At stage 1, only the cloud exists.
D) By stage 7, the star has reached the main sequence.
E) Nuclear reactions begin in the core by stage 4.

Back 30

E) Nuclear reactions begin in the core by stage 4.

Front 31

In the collapsing cloud fragment stage (stage 2) of star formation, the size of the cloud fragment is about
A) the size of the Solar System.
B) 100 times the size of the Solar System.
C) 10 times the size of the Solar System.
D) 1000 times the size of the Solar System.
E) 1/10th the size of the Solar System.

Back 31

B) 100 times the size of the Solar System.

Front 32

Stage 4 of star formation is when the object can exhibit violent surface activity producing extremely strong protostellar winds. This phase is also called the
A) protoplanetary nebula phase
B) T-Tauri phase
C) Herbig-Haro phase
D) protostar phase
E) brown dwarf phase

Back 32

B) T-Tauri phase

Front 33

What is the critical temperature at which hydrogen can fuse into helium in the star's core?
A) one million K
B) 5,800 K
C) 100 million K
D) 26,000 K
E) ten million K

Back 33

E) ten million K

Front 34

If the initial interstellar cloud in star formation has a mass sufficient to form hundreds of stars, how does a single star form from it?
A) A supernova blows the cloud up and dissipates the majority of the gas.
B) The cloud is disrupted by rotation so that it reduces its mass down to that of a typical star.
C) The cloud fragments into smaller clouds and forms many stars at one time.
D) One star forms and the rest of the matter goes into making planets, moons, and other objects of a solar system.
E) One star forms at its center and blows the rest of the matter back into space.

Back 34

C) The cloud fragments into smaller clouds and forms many stars at one time.

Front 35

At what stage of evolution do T Tauri stars occur?
A) just after the planetary nebula is expelled
B) when a protostar is on the verge of becoming a main sequence star
C) just as the collapsing cloud becomes luminous
D) after the star has established itself as a main sequence star
E) just prior to the protostar stage

Back 35

B) when a protostar is on the verge of becoming a main sequence star

Front 36

A star spends most of its life:
A) as a T Tauri variable star.
B) as a protostar.
C) as a main sequence star.
D) as a red giant or supergiant.
E) as a planetary nebula.

Back 36

C) as a main sequence star.

Front 37

The order of evolutionary stages of a star like the Sun would be Main Sequence, giant, planetary nebula, and finally:
A) neutron star.
B) black hole.
C) white dwarf.
D) nova.
E) hypernova.

Back 37

C) white dwarf.

Front 38

What is a typical age for a globular cluster?
A) 4.8 billion years
B) 200 million years
C) 12 billion years
D) one billion years
E) 10 million years

Back 38

C) 12 billion years

Front 39

What spectral type of star that is still around (not in a binary system) formed most recently?
A) F
B) M
C) A
D) K
E) O

Back 39

E) O

Front 40

Just as a low-mass main sequence star runs out of fuel in its core, it actually becomes brighter. How is this possible?
A) Helium fusion gives more energy than hydrogen fusion does, based on masses.
B) Its outer envelope is stripped away and we see the brilliant core.
C) It explodes.
D) It immediately starts to fuse helium.
E) The core contracts, raising the core temperature and increasing the size of the shell of hydrogen burning.

Back 40

E) The core contracts, raising the core temperature and increasing the size of the shell of hydrogen burning.

Front 41

Which of these will the Sun probably become in the very distant future?
A) supernova
B) planetary nebula
C) pulsar
D) hypernova
E) nova

Back 41

B) planetary nebula

Front 42

After a star has again evolved into a red giant:

Back 42

Hydrogen is still burning

Front 43

When a star becomes a red giant it becomes much brighter because it is:

Back 43

increasing in size.

Front 44

the event that marks the end of a stars evolutionary life just before becoming a white dwarf is a:

Back 44

Planetary Nebula

Front 45

the source of pressure that makes a white dwarf stable is:

Back 45

Electron degeneracy

Front 46

in a white dwarf the mass of the sun is packed into the volume of:

Back 46

Earth

Front 47

Which stars will end its main sequence life times most rapidly.

Back 47

The most massive star will consume fule the fastest

Front 48

Astronomers determine the age of star clusters by observing:

Back 48

The luminosity of stars at main sequence turn off point

Front 49

which of the following stars is probably the oldest?

Back 49

a1 solar mass white dwarf

Front 50

in a young star cluster, when ever massive stars are evolving into red giants the least massive stars are:

Back 50

Barley starting to fuel hydrogen

Front 51

If one star of a binary fills its Roche lobe and is spilling matter onto the other, the system is a:

Back 51

mass transfer binary

Front 52

total energy emitted by the brightest nova explosion is about:

Back 52

a million suns

Front 53

A white dwarf can explode when...

Back 53

its mass exceeds the Chandreskhar limit

Front 54

A nova includes...

Back 54

Mass transfer into a white dwarf in a binary system

Front 55

1.4 solar masses, the Chandrasekhar Limit.

Back 55

For a white dwarf to explode entirely as a Type I supernova, it's mass must be

Front 56

Supernova 1987A was important because?

Back 56

All of the above

Front 57

Open Star Cluster

Back 57

Mostly main sequence stars,
relatively young,
Smaller population
on the disk

Front 58

Globular Star clusters

Back 58

Branches off g type stars
Relatively old stars
bigger in population
above or below disk