What is the main sequence?
A) a region of cool, luminous stars in the upper right corner of the H-R diagram
B) a region of hot dim stars in the lower left corner of the H-R diagram
C) an approximately straight line on the H-R diagram along which 90% of stars lay
D) the order in which spectral types are listed

Question

Quizplus · Accepted Answer

The main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These plots are known as Hertzsprung-Russell diagrams. About 90% of stars, including the Sun, are found on the main sequence, where they spend the majority of their lifetimes fusing hydrogen into helium in their cores.

What Is the Main Sequence