Chapter 34, Problem 2RQ

What is a Cepheid?

To determine

The meaning of Cepheid.

Answer to Problem 2RQ

The Cepheid is a star which changes its brightness over a short period of time.

Explanation of Solution

A galaxy consists of many stars, and together these galaxies are known as the universe. In 1927, a huge telescope was built by Edwin Hubble, which made out individual stars within the Andromeda spiral nebula. The researcher mentioned that some of the stars were changing their brightness over a short period of time. These kinds of stars were termed as Cepheid.

The change in the illumination of the star would help astronomer to estimate the star's luminosity. Once the luminosity is determined, it would be easier to calculate stars' distance from the different galaxies. The Cepheid star is the regular radial pulsating stars that are considered to be ideal in order to calculate the distance.

Conclusion:

Therefore, the Cepheid is a star which changes its brightness over a short period of time.