Here's why:

* H-R Diagram: This diagram plots stars based on their luminosity (how bright they are) and their surface temperature (color).

* Main Sequence: This is a diagonal band on the H-R diagram where most stars spend the majority of their lives. Stars on the main sequence are fusing hydrogen into helium in their cores.

* Sun's Position: The Sun's luminosity and surface temperature place it squarely on the main sequence. It's considered a "yellow dwarf" star.

So, if you were to look at an H-R diagram, you'd find the Sun towards the middle of the main sequence, not too hot or too cool, not too large or too small.