Question 1

The object seen at the center of a planetary nebula is:

Accepted Answer

A) an accretion disk around a black hole. 
B) a planet in the process of forming. 
C) composed almost entirely of neutrons and is spinning rapidly. 
D) the former core of a red giant star, now a white dwarf star. 
A) an accretion disk around a black hole. 
B) a planet in the process of forming. 
C) composed almost entirely of neutrons and is spinning rapidly. 
D) the former core of a red giant star, now a white dwarf star. D

Question 2

Scientists were able to calculate the number of neutrinos released by SN 1987A over a 10-s period from the number ascertained at the detectors. In order to make this calculation, it was necessary to know the distance to the supernova and which one of the following pieces of information?

Accepted Answer

A) the energy of the neutrinos 
B) the speed of the neutrinos 
C) the size of SN 1987A 
D) the efficiency of the neutrino detectors 
A) the energy of the neutrinos 
B) the speed of the neutrinos 
C) the size of SN 1987A 
D) the efficiency of the neutrino detectors D

Question 3

In which order will a single star of about 1 M ? progress through its various stages of evolution?

Accepted Answer

A) T Tauri, main sequence, planetary nebula, and white dwarf 
B) planetary nebula, main sequence, neutron star, and black hole 
C) T Tauri, red giant, white dwarf, and neutron star 
D) planetary nebula, main sequence, red giant, and white dwarf 
A) T Tauri, main sequence, planetary nebula, and white dwarf 
B) planetary nebula, main sequence, neutron star, and black hole 
C) T Tauri, red giant, white dwarf, and neutron star 
D) planetary nebula, main sequence, red giant, and white dwarf A

Question 4

Dredge-ups occur when convection extends from deep within a star to the surface. Three of the following examples of deep convection can dredge up heavy elements to the surface. Which example does NOT dredge up heavy elements?

Accepted Answer

A) Convection in a red dwarf starts in the core. 
B) Convection starts deep within a star when it becomes a red giant for the first time. 
C) A dredge-up occurs when a star first becomes an asymptotic branch star. 
D) For stars more massive than about 2 M ? , a dredge-up occurs late in the asymptotic branch period. 
A) Convection in a red dwarf starts in the core. 
B) Convection starts deep within a star when it becomes a red giant for the first time. 
C) A dredge-up occurs when a star first becomes an asymptotic branch star. 
D) For stars more massive than about 2 M ? , a dredge-up occurs late in the asymptotic branch period.

Question 5

One peculiar feature of the evolution of a white dwarf star is that:

Accepted Answer

A) its size or radius slowly increases as it cools, until it becomes a red giant star. 
B) it heats as it shrinks because of the release of gravitational energy, ending up as a very hot but very small star. 
C) it shrinks as it cools, eventually to become a cold black hole in space. 
D) its size remains constant as it cools and dies. 
A) its size or radius slowly increases as it cools, until it becomes a red giant star. 
B) it heats as it shrinks because of the release of gravitational energy, ending up as a very hot but very small star. 
C) it shrinks as it cools, eventually to become a cold black hole in space. 
D) its size remains constant as it cools and dies.

Question 6

How bright will a star with the mass of the Sun become at the helium flash point, compared to its main-sequence luminosity?

Accepted Answer

A) 106 times brighter 
B) about 50% brighter 
C) 103 times brighter 
D) 10 times brighter 
A) 106 times brighter 
B) about 50% brighter 
C) 103 times brighter 
D) 10 times brighter

Question 7

Which of the following important components does a planetary nebula contribute to the interstellar medium?

Accepted Answer

A) nuclei of elements like carbon, nitrogen, and oxygen, which are major components of planets such as our own 
B) UV light that photoionizes hydrogen, which produces the red Balmer- light we see in emission nebulae 
C) rotational motion from the original star, which serves to concentrate interstellar matter into new stars and planetary systems 
D) new hydrogen nuclei, replenishing those which are lost when stars form 
A) nuclei of elements like carbon, nitrogen, and oxygen, which are major components of planets such as our own 
B) UV light that photoionizes hydrogen, which produces the red Balmer- light we see in emission nebulae 
C) rotational motion from the original star, which serves to concentrate interstellar matter into new stars and planetary systems 
D) new hydrogen nuclei, replenishing those which are lost when stars form

Question 8

How much fainter than a supernova is a typical nova?

Accepted Answer

A) 1 million times 
B) 10 times 
C) 100 million times 
D) 10,000 times 
A) 1 million times 
B) 10 times 
C) 100 million times 
D) 10,000 times

Question 9

A supernova is observed with no emission or absorption lines of hydrogen, helium, or silicon. What type of supernova is it?

Accepted Answer

A) Ia 
B) Ib 
C) Ic 
D) II 
A) Ia 
B) Ib 
C) Ic 
D) II

Question 10

A white dwarf star is supported from collapse under gravity by:

Accepted Answer

A) electron degeneracy pressure in the compact interior. 
B) centrifugal force due to rapid rotation. 
C) pressure of the gas, heated by nuclear fusion reactions in a shell around its core. 
D) pressure of the gas, heated by nuclear fusion reactions in its core. 
A) electron degeneracy pressure in the compact interior. 
B) centrifugal force due to rapid rotation. 
C) pressure of the gas, heated by nuclear fusion reactions in a shell around its core. 
D) pressure of the gas, heated by nuclear fusion reactions in its core.

Question 11

The majority of massive stars, at the point in time when they explode as supernovae, have become: (See Figure 20-14 of Universe, 11th ed.(in the text))

Accepted Answer

A) red supergiants. 
B) neutron stars. 
C) blue supergiants. 
D) white dwarfs. 
A) red supergiants. 
B) neutron stars. 
C) blue supergiants. 
D) white dwarfs.

Question 12

Interstellar dust contains graphite dust, made of pure carbon, along with other materials. Most of this carbon probably:

Accepted Answer

A) came from T Tauri stars through stellar winds. 
B) came from carbon stars, through stellar mass loss. 
C) was produced in the Big Bang at the time of the creation of the universe. 
D) was produced in supernova explosions. 
A) came from T Tauri stars through stellar winds. 
B) came from carbon stars, through stellar mass loss. 
C) was produced in the Big Bang at the time of the creation of the universe. 
D) was produced in supernova explosions.

Question 13

The stars that eventually become white dwarfs are those that start life with masses of less than about

Accepted Answer

A) 1.4 M ? 
B) 3 M ? 
C) 25 M ? 
D) 4 M ? 
A) 1.4 M ? 
B) 3 M ? 
C) 25 M ? 
D) 4 M ?

Question 14

Out of all matter ejected into the interstellar medium each year by stars, planetary nebula shell ejections account for:

Accepted Answer

A) almost 100%. 
B) just over half. 
C) less than 1%. 
D) about 15%. 
A) almost 100%. 
B) just over half. 
C) less than 1%. 
D) about 15%.

Question 15

The core of a planetary nebula has an initial surface temperature of 100,000 K. If it radiates like a blackbody, in what electromagnetic region will the peak of its radiation spectrum lie?

Accepted Answer

A) radio 
B) visible 
C) ultraviolet 
D) gamma ray 
A) radio 
B) visible 
C) ultraviolet 
D) gamma ray

Question 16

Asymptotic branch stars are important for enriching the interstellar medium with heavy elements and molecules. Three of the following statements correctly describe reasons for this enrichment, and one does NOT. Which is the EXCEPTION?

Accepted Answer

A) These stars have relatively cool surfaces. 
B) These stars have strong stellar winds. 
C) These stars have convective zones that extend deep into the star. 
D) These stars have shell fusion occurring just beneath the surface. 
A) These stars have relatively cool surfaces. 
B) These stars have strong stellar winds. 
C) These stars have convective zones that extend deep into the star. 
D) These stars have shell fusion occurring just beneath the surface.

Question 17

Measurements from distant galaxies indicate that supernovae should occur at a rate of two per century in a spiral galaxy such as the Milky Way, but only three have been recorded in our galaxy in the past 1000 years. Why is this?

Accepted Answer

A) Most supernovae produce x rays and radio waves but not visible light, and hence were invisible to earlier observers. 
B) The majority of supernovae must have occurred in the plane of the Milky Way, and hence were hidden from Earth by the dense gas and dust in the Milky Way plane. 
C) Observers were not watching the sky carefully enough, particularly through the Dark Ages and over the past few centuries. 
D) The Milky Way Galaxy is somehow different, with much lower numbers of very massive stars in general, so many fewer stars have undergone supernova explosions. 
A) Most supernovae produce x rays and radio waves but not visible light, and hence were invisible to earlier observers. 
B) The majority of supernovae must have occurred in the plane of the Milky Way, and hence were hidden from Earth by the dense gas and dust in the Milky Way plane. 
C) Observers were not watching the sky carefully enough, particularly through the Dark Ages and over the past few centuries. 
D) The Milky Way Galaxy is somehow different, with much lower numbers of very massive stars in general, so many fewer stars have undergone supernova explosions.

Question 18

What will be the consequences for the planetary system when the Sun evolves to the asymptotic giant branch (AGB) phase of its evolution?

Accepted Answer

A) The whole planetary system will melt and vaporize. 
B) The whole system will survive almost intact, but the planets will be driven outward from their present orbits by the intense solar wind. 
C) The planetary system will be slowly drawn into the core of the Sun by the gravitational field of the high-density core. 
D) The inner planets will melt and vaporize, but Jupiter and the outer planets will survive, after losing their outer atmospheres. 
A) The whole planetary system will melt and vaporize. 
B) The whole system will survive almost intact, but the planets will be driven outward from their present orbits by the intense solar wind. 
C) The planetary system will be slowly drawn into the core of the Sun by the gravitational field of the high-density core. 
D) The inner planets will melt and vaporize, but Jupiter and the outer planets will survive, after losing their outer atmospheres.

Question 19

During its lifetime, the Sun will experience all of the following energy sources EXCEPT:

Accepted Answer

A) Kelvin-Helmholtz gravitational contraction. 
B) hydrogen burning. 
C) helium burning. 
D) carbon burning. 
A) Kelvin-Helmholtz gravitational contraction. 
B) hydrogen burning. 
C) helium burning. 
D) carbon burning.

Question 20

The next element in the periodic table after tin (chemical symbol Sn) is antimony (chemical symbol Sb). If 122Sn captures a neutron, the result will be:

Accepted Answer

A) 123Sn. 
B) 123Sb. 
C) 121Sn. 
D) 122Sb. 
A) 123Sn. 
B) 123Sb. 
C) 121Sn. 
D) 122Sb.

Exam 20: Stellar Evolution: The Death of Stars

The object seen at the center of a planetary nebula is:

Scientists were able to calculate the number of neutrinos released by SN 1987A over a 10-s period from the number ascertained at the detectors. In order to make this calculation, it was necessary to know the distance to the supernova and which one of the following pieces of information?

In which order will a single star of about 1 M ? progress through its various stages of evolution?

Dredge-ups occur when convection extends from deep within a star to the surface. Three of the following examples of deep convection can dredge up heavy elements to the surface. Which example does NOT dredge up heavy elements?

One peculiar feature of the evolution of a white dwarf star is that:

How bright will a star with the mass of the Sun become at the helium flash point, compared to its main-sequence luminosity?

Which of the following important components does a planetary nebula contribute to the interstellar medium?

How much fainter than a supernova is a typical nova?

A supernova is observed with no emission or absorption lines of hydrogen, helium, or silicon. What type of supernova is it?

A white dwarf star is supported from collapse under gravity by:

The majority of massive stars, at the point in time when they explode as supernovae, have become: (See Figure 20-14 of Universe, 11th ed.(in the text))

Interstellar dust contains graphite dust, made of pure carbon, along with other materials. Most of this carbon probably:

The stars that eventually become white dwarfs are those that start life with masses of less than about

Out of all matter ejected into the interstellar medium each year by stars, planetary nebula shell ejections account for:

The core of a planetary nebula has an initial surface temperature of 100,000 K. If it radiates like a blackbody, in what electromagnetic region will the peak of its radiation spectrum lie?

Asymptotic branch stars are important for enriching the interstellar medium with heavy elements and molecules. Three of the following statements correctly describe reasons for this enrichment, and one does NOT. Which is the EXCEPTION?

Measurements from distant galaxies indicate that supernovae should occur at a rate of two per century in a spiral galaxy such as the Milky Way, but only three have been recorded in our galaxy in the past 1000 years. Why is this?

What will be the consequences for the planetary system when the Sun evolves to the asymptotic giant branch (AGB) phase of its evolution?

During its lifetime, the Sun will experience all of the following energy sources EXCEPT:

The next element in the periodic table after tin (chemical symbol Sn) is antimony (chemical symbol Sb). If 122Sn captures a neutron, the result will be:

Astronomy and the Universe

Knowing the Heavens

Eclipses and the Motion of the Moon

Gravitation and the Waltz of the Planets

The Nature of Light

Optics and Telescopes

Comparative Planetology I: Our Solar System

Comparative Planetology II: the Origin of Our Solar System

The Living Earth

Our Barren Moon

Mercury, Venus, and Mars: Terrestrial, yet Unique

Jupiter and Saturn: Lords of the Planets

Jupiter and Saturns Satellites of Fire and Ice

Uranus, Neptune, Pluto, and the Kuiper Belt: Remote Worlds

Asteroids, Comets, and Impacts

Our Star, the Sun

The Nature of the Stars

The Birth of Stars

Stellar Evolution: on and After the Main Sequence

Stellar Remnants: Neutron Stars and Black Holes

Our Galaxy

Galaxies

Quasars and Active Galaxies

Cosmology: The Origin and Evolution of the Universe

Exploring the Early Universe

The Search for Extraterrestrial Life

Filters

The next element in the periodic table after tin (chemical symbol Sn) is antimony (chemical symbol Sb). If ¹²²Sn captures a neutron, the result will be: