Cepheid variable stars are useful to astronomers as indicators of
A) stars with very high-speed motion.
B) white dwarf star behavior.
C) the existence of black holes.
D) distance, particularly to nearby galaxies.

Question

Quizplus · Accepted Answer

Cepheid variable stars are used as standard candles by astronomers to measure distances, especially to nearby galaxies, due to their well-defined period-luminosity relationship.

Cepheid Variable Stars Are Useful to Astronomers as Indicators of