13. Between the time when a star uses up its hydrogen fuel and the
time when it starts burning helium, the star _______________, and its
luminosity ________________.
a. contracts; decreases
b. contracts; increases
c. expands; decreases
d. expands; increases
14. Two star clusters, Cluster A and Cluster B, are observed. Cluster A
has many bright blue stars and many very dim red stars. Cluster B has no
bright blue stars, but has many bright red stars along with many very dim
red stars. What can we infer?
a. Cluster A is much younger than Cluster B
b. Cluster A is much older than Cluster B
c. Cluster A is much more massive than Cluster B
d. Cluster A is much less massive than Cluster B
15. What is an isochrone?
a. the age of a cluster, determined from the cluster's H-R diagram
b. the path a star follows as it evolves off the Main Sequence
c. a line in the H-R diagram connecting stars that have the same mass
and different ages
d. a line in the H-R diagram connecting stars that have the same age
and different masses
16. What is an evolutionary track?
a. the part of the H-R diagram where helium-burning stars are found
b. the point where a cluster's most massive stars still on the Main Sequence
are found
c. the path a star follows through the H-R diagram as it ages
d. a line in the H-R diagram connecting the stars in a cluster
17. Which of the following is the correct evolutionary sequence for a
one-solar-mass star?
a. protostar, horizontal branch star, asymptotic giant, Main Sequence star,
red giant, white dwarf
b. protostar, Main Sequence star, red giant, horizontal branch star,
asymptotic giant, white dwarf
c. protostar, asymptotic giant, Main Sequence star, horizontal branch star,
red giant, white dwarf
d. protostar, Main Sequence star, asymptotic giant, horizontal branch star,
red giant, white dwarf
18. A/an ________________ is a star that is undergoing steady helium fusion
in its core.
a. red giant
b. horizontal branch star
c. Main Sequence star
d. asymptotic giant
19. What is a planetary nebula?
a. the disk around a young star
b. the shell of a dying star that has become separated from its core
c. a very large giant star that has swallowed its planets
d. any glowing cloud of gas found near the ecliptic