A star in the instability strip of the H- R diagram would
A) explode as a Type I supernova.
B) vary in both temperature and radius.
C) vary in temperature and radius, but not in brightness.
D) vary in brightness with an irregular pattern.
E) vary in temperature and brightness, but not in radius.

Question

Quizplus · Accepted Answer

Stars in the instability strip of the Hertzsprung-Russell (H-R) diagram, such as Cepheid variables, are known to pulsate, causing them to vary in both temperature and radius. This variation leads to changes in their brightness, making them important standard candles for measuring cosmic distances.

A Star in the Instability Strip of the H- R