Chapter 17
Basic Skills/Definitions Quiz
Part A
Which star will live longer?
Hint A.1
Study Section 17.1.
ANSWER:

1 solar-mass star 3 solar-mass star 4 solar mass star. 2 solar-mass star
Part B
In the context of understanding stellar lives, by "high-mass" stars we mean:
Hint B.1
Study Section 17.1
ANSWER:

stars like our Sun. stars with mass more than about 8 times the mass of our Sun. stars with mass more than about 3 times the mass of our Sun. all stars, since all stars are far more massive than planets.
Part C
Where are the carbon atoms in your body made?
Hint C.1
Study Section 17.2
ANSWER:

Plants. Red giant stars. Supernova explosions of massive stars. The Big Bang.
Part D
Where is the element gold made?
Hint D.1
Study Section 17.3
ANSWER:

The Big Bang. Supernova explosions of massive stars. Red giant stars. Magma rock just below the Earth's crust.
Part E
Which pair of atomic nuclei feel the largest repulsive electromagnetic force between the two of them?
Hint E.1
Study Section 17.3
ANSWER:

Hydrogen and deuterium ("heavy hydrogen") Hydrogen and Helium Helium and Helium. Hydrogen and Hydrogen.
Part F
Which of the following stars will certainly end its life as a supernova?
Hint F.1
Study Section 17.1-17.3
ANSWER:

The Sun. 10 solar mass star red giant star. 5 solar mass stars.
Part G
In order to predict whether a star will eventually fuse oxygen into a heavier element, you mainly want to know what fact about the star?
Hint G.1
Study Section 17.3
ANSWER:

The star's heavy element abundance. The star's mass. The star's constellation. The star's luminosity.
Part H
Which star does not have fusion occurring in its core?
Hint H.1
Study Section 17.2-17.3
ANSWER:

Main sequence star Helium burning star. Horizontal branch stars. Red giant.
Part I
Which of the following lists the stages of life for a low-mass star in the correct order?
Hint I.1
Study Section 17.3
ANSWER:

protostar, main-sequence star, red giant, planetary nebula, white dwarf protostar, main-sequence star, planetary nebula, red giant protostar, main-sequence star, red giant, supernova, neutron star main-sequence star, white dwarf, red giant, planetary nebula, protostar
Part J
When a main-sequence star exhausts its core hydrogen fuel supply:
Hint J.1
Study Section 17.2
ANSWER:

the star becomes a neutron star. the entire star shrinks in size. the core shrinks while the rest of the star expands. the core immediately begins to fuse its helium into carbon.
Part K
The main source of energy for a star as it grows in size to become a red giant is ______.
Hint K.1
Study Section 17.2.
ANSWER:

hydrogen fusion in the core. hydrogen fusion in a shell surrounding the central core. helium fusion in the core. gravitational contraction.
Part L
The overall helium fusion reaction is:
Hint L.1
Study Section 17.2
ANSWER:

two hydrogen nuclei fuse to form one helium nucleus. Four helium nuclei fuse to form one oxygen nucleus. two helium nuclei fuse to form one beryllium nucleus. three helium nuclei fuse to form one carbon nucleus.
Part M
What is a helium flash?
Hint M.1
Study Section 17.2
ANSWER:

The sudden onset of helium fusion in the core of a low-mass star. A sudden brightening of a low-mass star, detectable from Earth by observing spectral lines of helium. The ignition of helium shell burning in a high-mass star with a carbon core. It is another name for the helium fusion reaction.
Part N
Which of the following statements about horizontal branch stars is true?
Hint N.1
Study Section 17.2
ANSWER:

In a particular star cluster, all horizontal branch stars have about the same temperature and color. Horizontal branch stars are red giants. Both hydrogen fusion and helium fusion are occurring in horizontal branch stars. Horizontal branch stars have inert (non-burning) carbon cores.
Part O
What is a planetary nebula?
Hint O.1
Study Section 17.2
ANSWER:

The remains of a high-mass star that has exploded. Interstellar gas from which planets are likely to form in the not-too-distant future. Gas ejected from a low-mass star in the final stage of its life. Gas created from the remains of planets that once orbited a dead star.
Part P
The ultimate fate of our Sun is to _____.
Hint P.1
Study Section 17.2
ANSWER:

become a black hole. explode in a supernova. become a rapidly spinning neutron star. become a white dwarf that will slowly cool with time.
Part Q
What is the CNO cycle?
Hint Q.1
Study Section 17.3
ANSWER:

It is the series of fusion reactions that have produced all the carbon, nitrogen, and oxygen in the universe. The CNO cycle is the process by which helium is fused into carbon, nitrogen, and oxygen. The CNO cycle is series of nuclear reactions with the final result being the fusion of four hydrogen nuclei into one helium nucleus. The CNO cycle is the process by which carbon is fused into nitrogen and oxygen
Part R
Why is iron significant to understanding how a supernova occurs?
Hint R.1
Study Section 17.3
ANSWER:

Supernovae often leave behind neutron stars, which are made mostly of iron. Iron cannot release energy either by fission or fusion, so a star with an iron core has no way to generate additional energy to counteract the crush of gravity. Iron is the heaviest of all atomic nuclei, and thus no heavier elements can be made. The fusion of iron into uranium is the reaction that drives a supernova explosion.
Part S
After a supernova explosion, the remains of the stellar core ______.
Hint S.1
Study Section 17.3
ANSWER:

may be either a white dwarf, neutron star, or black hole. may be either a neutron star or a black hole. will always be a neutron star. will always be a black hole.
Part T
Why is Supernova 1987A particularly important to astronomers?
Hint T.1
Study Section 17.3
ANSWER:

It occurred only a few light-years from Earth. It provided the first evidence that supernovae really occur. It is the nearest supernova to have occurred at a time when we were capable of studying it carefully with telescopes. It was the first supernova detected in nearly 400 years.
Part U
Algol consist of a 3.7 Msun main-sequence star and a 0.8 Msun subgiant. Why does this seem surprising, at least at first?
Hint U.1
Study Section 17.4
ANSWER:

The two stars in a binary system should both be at the same stage of life; that is, they should either both be main sequence stars or both be subgiants. A star with a mass of 3.7 Msun is too big to be a main sequence star. The two stars should be the same age, so we'd expect the subgiant to be more massive than the main-sequence star. It doesn't make sense to find a subgiant in a binary star system.