Multiple Choice
The Cepheid variables that Hubble observed in M31 had an apparent magnitude of about 18, and thus an apparent brightness relative to the Sun (b/bŸ) of about 1.3 × 10-18. What approximate periods would these Cepheids need in order to yield a distance to M31 of about 750 kpc?
A) less than 1 day
B) 3 days
C) 10 days
D) 70 days
Correct Answer:
Verified
Correct Answer:
Verified
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