Multiple Choice
One reason that Cepheid stars are important to astronomers is that
A) They are especially rich in metal content
B) There is a definite relationship between variability period and luminosity
C) They are all in the plane of the galaxy-so center can be measured
D) They can be seen even in distant clusters of galaxies
E) They are very young,so stellar evolution can be studied in detail
Correct Answer:

Verified
Correct Answer:
Verified
Q18: Which of the following is a key
Q19: Massive stars on the upper end of
Q20: What element is produced by the triple-alpha
Q21: The age of a cluster can be
Q22: Cluster A has no stars of spectral
Q24: Estimate the main sequence lifetime for a
Q25: What limits the formation of giant stars
Q26: What causes Cepheid variables to vary in
Q27: As soon as its core hydrogen is
Q28: Based on your knowledge of the H-R