When a Cepheid variable star reaches maximum luminosity, which other property of the star does NOT also reach a maximum?
A)surface temperature
B)diameter
C)outward radial velocity
D)luminosity

Question

Quizplus · Accepted Answer

When a Cepheid variable star reaches maximum luminosity, its diameter does not also reach a maximum. Instead, the diameter decreases as the outer layers of the star are pushed outward by the pulsations, causing them to cool and become less luminous. This is known as the "radius-luminosity" relationship and is used to determine the distance to Cepheid variable stars.

When a Cepheid Variable Star Reaches Maximum Luminosity, Which Other