Astronomy a beginners guide to the universe 8th CHaisson mcmillan chapter 12 clicker questions

Stars like our Sun will end their lives asExplanation: Low-mass stars eventually swell into red giants, and their cores later contract into white dwarfs... Explanation: Massive stars cre

Stars like our Sun will end their lives as

Stars like our Sun will end their lives as

Explanation: Low-mass stars

eventually swell into red giants,

and their cores later contract

into white dwarfs

Elements heavier than hydrogen and helium were created

a) in the Big Bang

b) by nucleosynthesis in massive stars

c) in the cores of stars like the Sun

d) within planetary nebula

e) They have always existed

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Elements heavier than hydrogen and helium were created

a) in the Big Bang

b) by nucleosynthesis in massive stars

c) in the cores of stars like the Sun

d) within planetary nebula

e) They have always existed

Explanation: Massive stars

create enormous core

temperatures as red

supergiants, fusing helium

into carbon, oxygen, and even

heavier elements

The Sun will evolve away from the main sequence when

a) its core begins fusing iron

b) its supply of hydrogen is used up

c) the carbon core detonates, and it explodes as a Type I supernova

d) helium builds up in the core, while the hydrogen-burning

shell expands

e) the core loses all of its neutrinos, so all fusion ceases

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The Sun will evolve away from the main sequence when

a) its core begins fusing iron

b) its supply of hydrogen is used up

c) the carbon core detonates, and

it explodes as a Type I supernova

d) helium builds up in the core,

while the hydrogen-burning shell expands.

e) the core loses all of its neutrinos, so all fusion ceases

Explanation: When the Sun’s core becomes unstable and contracts, additional H fusion generates extra pressure, and the star will swell into a red giant

The helium flash occurs

a) when T-Tauri bipolar jets shoot out

b) in the middle of the main-sequence stage

c) in the red giant stage

d) during the formation of a neutron star

e) in the planetary nebula stage

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The helium flash occurs

a) when T-Tauri bipolar jets shoot out

b) in the middle of the main-sequence stage

c) in the red giant stage.

d) during the formation of a neutron star

e) in the planetary nebula stage

Explanation: When the collapsing

core of a red giant reaches high

enough temperatures and

densities, helium can fuse into

carbon quickly—a helium flash

Stars gradually lose mass as they become white dwarfs during the

a) T-Tauri stage

b) emission nebula stage

c) supernova stage

d) nova stage

e) planetary nebula stage

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Stars gradually lose mass as they become white dwarfs during the

a) T-Tauri stage

b) emission nebula stage

c) supernova stage

d) nova stage

e) planetary nebula stage.

Explanation: Low-mass stars forming

white dwarfs slowly lose their outer

atmospheres and illuminate these

gases for a relatively short time

Astronomers determine the age of star clusters by observing

a) the number of main-sequence stars

b) the ratio of giants to supergiants

c) the luminosity of stars at

the turnoff point

d) the number of white dwarfs

e) supernova explosions

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Astronomers determine the age of star clusters by observing

a) the number of main-sequence stars

b) the ratio of giants to supergiants

c) the luminosity of stars at

the turnoff point.

d) the number of white dwarfs

e) supernova explosions

Explanation: The H–R diagram

of a cluster can indicate its

approximate age

Turnoff point from the main sequence

The source of pressure that makes a white dwarf stable is

The source of pressure that makes a white dwarf stable is

Explanation: Electrons in the core

cannot be squeezed infinitely close

and prevent a low-mass star from

collapsing further

In a white dwarf, the mass of the Sun is packed into the volume of

a) an asteroid

b) a planet the size of Earth

c) a planet the size of Jupiter

d) an object the size of the Moon

e) an object the size of a sugar cube

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In a white dwarf, the mass of the Sun is packed into the volume of

a) an asteroid

b) a planet the size of Earth.

c) a planet the size of Jupiter

d) an object the size of the Moon

e) an object the size of a

sugar cube

Explanation: The density of a white dwarf is about a million times greater than normal solid matter

In a young star cluster, when more massive stars are evolving into red giants, the least massive stars are

a) ending their main-sequence stage

b) also evolving into red giants

c) forming planetary nebulae

d) barely starting to fuse hydrogen

e) starting the nova stage

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In a young star cluster, when more massive stars are evolving into red giants, the least massive stars are

a) ending their main-sequence stage

b) also evolving into red giants

c) forming planetary nebulae

d) barely starting to fuse

hydrogen.

e) starting the nova stage

Explanation: More massive stars

form much faster and have much

shorter main-sequence lifetimes

Low-mass stars form more slowly

A star will spend most of its “shining” lifetime

a) as a protostar

b) as a red giant

c) as a main-sequence star

d) as a white dwarf

e) evolving from type O to type M

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A star will spend most of its “shining” lifetime

a) as a protostar

b) as a red giant

c) as a main-sequence star.

d) as a white dwarf

e) evolving from type O to type M

Explanation: In the

main-sequence stage, hydrogen

fuses to helium Pressure from

light and heat pushing out

balances gravitational pressure

pushing inward

A nova involves

a) mass transfer onto a white dwarf in a binary star system

b) repeated helium fusion flashes in red giants

c) rapid collapse of a protostar into a massive O star

d) the explosion of a low-mass star

e) the birth of a massive star in a new cluster

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A nova involves

a) mass transfer onto a white dwarf in a binary star system

b) repeated helium fusion flashes in red giants

c) rapid collapse of a protostar into a massive O star

d) the explosion of a low-mass star

e) the birth of a massive star in a new cluster

Explanation: Sudden, rapid fusion

of new fuel dumped onto a white

dwarf causes the star to flare up

and for a short time become much

brighter

What type of atomic nuclei heavier than helium are most common, and why?

a) Those heavier than iron, because of supernovae

b) Iron, formed just before massive stars explode

c) Odd-numbered nuclei, built with hydrogen fusion

d) Even-numbered nuclei, built with helium fusion

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What type of atomic nuclei heavier than helium are most common, and why?

a) Those heavier than iron, because of supernovae

b) Iron, formed just before massive stars explode

c) Odd-numbered nuclei, built with hydrogen fusion

d) Even-numbered nuclei, built

with helium fusion

Explanation: Helium nuclei have

an atomic mass of 4; they act as

building blocks in high-temperature

fusion within supergiants

A white dwarf can explode when

a) its mass exceeds the Chandrasekhar limit

b) its electron degeneracy increases enormously

c) fusion reactions increase in its core

d) iron in its core collapses

e) the planetary nebula stage ends

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A white dwarf can explode when

a) its mass exceeds the Chandrasekhar limit.

b) its electron degeneracy increases enormously

c) fusion reactions increase in its core

d) iron in its core collapses

e) the planetary nebula stage ends

Explanation: If

additional mass from

a companion star

pushes a white dwarf

beyond 1.4 solar masses,

it can explode in a Type I supernova

A Type II supernova occurs when

a) hydrogen fusion shuts off

b) uranium decays into lead

c) iron in the core starts to fuse

d) helium is exhausted in the outer layers

e) a white dwarf gains mass

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A Type II supernova occurs when

a) hydrogen fusion shuts off

b) uranium decays into lead

c) iron in the core starts to fuse.

d) helium is exhausted in the outer layers

e) a white dwarf gains mass

Explanation: Fusion of iron

does not produce energy

or provide pressure; the

star’s core collapses

immediately, triggering a supernova explosion

Supernova 1987A was important because

a) its parent star had been studied before the explosion

b) its distance was already known

c) it was observed early, as its light was still increasing

d) its evolution was captured with detailed images from

the Hubble Space Telescope.

e) All of the above are true

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Supernova 1987A was important because

a) its parent star had been studied before the explosion

b) its distance was already known

c) it was observed early, as its light was still increasing

d) its evolution was captured with

detailed images from the

Hubble Space Telescope.

e) All of the above are true.

Explanation: Supernovae are important

distance indicators in the study of

galaxies beyond the Milky Way

As stars evolve during their main-sequence lifetime,

a) they gradually become cooler and dimmer (spectral type O to type M)

b) they gradually become hotter and brighter (spectral type M to type O)

c) they don’t change their spectral type

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As stars evolve during their main-sequence lifetime,

a) they gradually become cooler and dimmer (spectral type O to type M)

b) they gradually become hotter and brighter (spectral type M to type O)

c) they don’t change their spectral type.

Explanation: A star’s main-sequence characteristics of surface temperature and brightness are based on its mass Stars of different initial mass become different spectral types on the

main sequence

More massive white dwarfs are _ compared with less massive white dwarfs.

More massive white dwarfs are _ compared with less massive white dwarfs.