Why are Cepheid variables important?
A)Cepheids variables are pulsating stars whose pulsation periods are directly related to their true luminosities. Therefore they can be used as distance indicators.
B)Cepheids variables are supermassive stars that are on the verge of becoming supernovae. Therefore they allow us to choose candidates to watch if we hope to observe a supernova.
C)Cepheids variables are a type of irregular galaxy, much more common in the early universe. Therefore they help to understand how galaxies formed.
D)Cepheid variables are stars that vary in brightness because they harbor a black hole. Therefore, they provide direct evidence for black holes.

Question

Quizplus · Accepted Answer

Cepheid variables are important because they serve as reliable distance indicators. Their pulsation periods are directly related to their true luminosities, which means that astronomers can use the observed period to determine the star's intrinsic brightness, and from there, calculate its distance. This has been essential for measuring distances to nearby galaxies and determining the scale of the universe.

Why Are Cepheid Variables Important