Stellar Evolution - Quiz 13

1. Which of the following sequences below correctly describes the evolution of the Sun from young to old?
A).. White dwarf, red giant, main-sequence, protostar
B)..Red giant, main-sequence, white dwarf, protostar
C).. Protostar, red giant, main-sequence, white dwarf
D)..Protostar, main-sequence, white dwarf, red giant
E)..Protostar, main-sequence, red giant, white dwarf

2. A planetary nebula is
A)... another term for the disk of gas around a young star.
B)... the cloud from which protostars form.
C)...a shell of gas ejected from a star late in its life.
D)...what is left when a white dwarf star explodes as a supernova.
E)...the remnants of the explosion created by the collapse of the iron core in a massive star.

3. Stars like the Sun probably do not form iron cores during their evolution because
A)... all the iron is ejected when they become planetary nebulas.
B)... their cores never get hot enough for them to make iron by nucleosynthesis.
C)...the iron they make by nucleosynthesis is all fused into uranium.
D)... their strong magnetic fields keep their iron in their atmospheres.
E)... None of the above.

4. As a star like the Sun evolves into a red giant, its core
A)... expands and cools.
B)... contracts and heats.
C)...expands and heats.
D)... turns into iron.
E)...turns into uranium.

5. A star whose mass is 5 times larger than the Sun's and whose luminosity is 100 times larger than the Sun's has a main-sequence lifetime about
A)... 5 times longer than the Sun's.
B)... 500 times longer than the Sun's.
C)... 5 times shorter than the Sun's.
D)... 100 times shorter than the Sun's.
E)... 20 times shorter than the Sun's.

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