What important role do Cepheid variables stars have in astronomy?
A) distance measurements to distant galaxies
B) the determination of stellar luminosities
C) the determination of speeds of stars in galactic arms from the Doppler shift of their spectra
D) the keeping of accurate time

Question

Quizplus · Accepted Answer

Cepheid variable stars have a well-defined relationship between their luminosity and pulsation period, which allows astronomers to measure distances to distant galaxies by comparing their apparent brightness with their intrinsic brightness.

What Important Role Do Cepheid Variables Stars Have in Astronomy