Hertzsprung - Russell Diagram

1. The Hertzsprung- Russell diagram is important to astronomy because  it can be used to define different types of stars and to match theoretical predictions of stellar evolution, using computer models with observations of actual stars. 

2.The original diagram displayed the spectral type of stars on the horizontal axis and the absolute magnitude on the vertical axis, that is the first quality the HR Diagram measures. The second quality is measures is the effective surface temperature of the star on one axis and the luminosity of the star on the other

3. The sun if found on the main sequence at luminosity. 

All credit given to Bridgette Castillo. I did not input any content into this blog post. 10/29/12 @ 10:22 am.