What do we call the region of the HR diagram that represents giant stars that are fusing helium in their cores and then in their shells?
A)turnoff point
B)horizontal branch
C)turn-on point
D)main sequence

Question

Quizplus · Accepted Answer

The region of the HR diagram that represents giant stars fusing helium in their cores and shells is called the horizontal branch. This is located to the right of the main sequence and is characterized by a relatively stable luminosity as the star undergoes changes in temperature and radius. The turnoff point is the location where stars are leaving the main sequence, the turn-on point is not a recognized term in this context, and the main sequence represents stars that are fusing hydrogen in their cores.

What Do We Call the Region of the HR Diagram