What two observable properties of a Cepheid variable are directly related to one another?
A)the period between its peaks of brightness and its distance
B)its luminosity and its mass
C)the period between its peaks of brightness and its luminosity
D)its mass and its distance

Question

Quizplus · Accepted Answer

The period between the peaks of brightness of a Cepheid variable and its luminosity are directly related to one another. This means that astronomers can use an observed period to estimate the star's luminosity, which in turn can be used to calculate its distance. This relationship is known as the period-luminosity relationship, and it has been used to measure distances to many galaxies beyond our own Milky Way. The other choices listed are not directly related to each other in the same way as the period-luminosity relationship.

What Two Observable Properties of a Cepheid Variable Are Directly