Question

Choose the correct option: The method of measuring the distance to stars beyond 100 light-years is:
A) Cepheid variable stars
B) Heid variable stars
C) Lowheid variable stars
D) None

Answer 1

Hint:It is a type of star or intrinsic variable that pulsates radially in a predictable way. These stars are supergiants with brightness from 500 to 30,000 times greater than that of the Sun but their surface temperatures are similar. This particular method of measuring the distance to stars was discovered by American astronomer Henrietta Swan Leavitt in 1908.

Complete step by step answer:The method of measuring the distance to stars beyond 100 light-years is the Cepheid variable stars. We know that the brightness of stars changes over time and astronauts can figure out the true brightness by observing the change in this brightness over time. Now, they can calculate the distance to the star by comparing the apparent brightness of the star to the true brightness. This particular method of measuring the distance to stars was discovered by American astronomer Henrietta Swan Leavitt in 1908. This method was used in the early 20^th century to measure the distances to many globular clusters.

Additional information:A Cepheid variable is a type of star or intrinsic variable that pulsates radially in a predictable way. It varies in both diameter and temperature and produces changes in brightness with a well-defined stable period and amplitude. As their variation in brightness is due to a physical change within the star and also due to the periodic expansion and contraction of the surface layers of the stars the Cepheid stars pulsate. These stars are supergiants with brightness from 500 to 30,000 times greater than that of the Sun. Though their surface temperatures are similar to the Sun's temperature.

Note:Cepheid variable stars are extremely bright and dwell as a very distant one that can be observed and measured. Once someone calculates the period of a distant Cepheid, its brightness can be determined by observing its known behavior. Then by relating the distance modulus equation with its absolute magnitude and apparent magnitude, its distance can be determined, and thus Cepheid variable stars can be used to measure distances to stars beyond 100 light years.