12. Which star will leave the Main Sequence first?
a. Alpha Centauri A, because it is more massive
b. Alpha Centauri B, because it is less massive
c. they will both leave at the same time, because they were born together
d. there is no way to tell, because the stars are touching each other and
exchanging mass
13. When does a protostar become a star?
a. when it begins to fuse hydrogen in its core
b. when its mass becomes greater than half a solar mass
c. when the peak of its spectrum moves into visible light
d. when the cloud of gas and dust around it is cleared away
14. Which phase in a low-mass star's evolution lasts longest?
a. protostar
b. Main Sequence
c. red giant
d. horizontal branch
15. What is the difference between a red giant and an asymptotic giant?
a. an asymptotic giant's interior is like a red giant's, but its surface
is hotter, so it's not red
b. high-mass stars become red giants; low-mass stars become asymptotic
giants
c. an asymptotic giant is a star that is traveling up the giant branch
and will eventually become a red giant
d. a red giant has a degenerate helium core; an asymptotic giant has a
degenerate carbon core
16. The Pleiades and the Hyades are two star clusters in the constellation
of Taurus. The Pleiades has many bright blue stars but no bright red
stars, and the Hyades has many bright red stars and few bright blue stars.
What can we conclude?
a. the Pleiades is older than the Hyades
b. the Hyades is older than the Pleiades
c. the Pleiades is closer than the Hyades
d. the Hyades is closer than the Pleiades
17. Drs. Harden, Petrie, and Rozyczka discover a binary system consisting
of a white dwarf of about 1.4 solar masses and a red giant of about 2
solar masses. They report that the red giant seems to be losing mass,
which is going onto the white dwarf. What will happen to this system
when the white dwarf exceeds the Chandrasekhar limit?
a. the white dwarf will collapse into a black hole
b. a Type I supernova
c. a Type II supernova
d. mass will start flowing back onto the red giant