Question

Consider an HR Diagram. What is represented by the vertical axis? The horizontal axis? Explain where on this diagram (upper left, middle, lower right, middle left, etc.) you might find the following eight items: the main sequence region, the variable star region, the black dwarf region, the red dwarf region, the white dwarf region, the red giant region, the blue giant region, and the location of our Sun.

Answer 1

The H-R diagram is not a standard graph: for historical reasons, the horizontal axis' values increase from right to left, instead of the more common left to right.The vertical axis shows the increase in total power output from stars( luminosity).The horizontal axis shows the increase in surface temperature of stars.

The main sequence region - Middle

The variable star region - Upper Left

The black dwarf region - lower right

The red dwarf region - lower right

The white dwarf region - Lower Left

The red giant region - Red Middle

The blue giant region - Left Middle

The location of our Sun - Middle