1. Color of a star is an indicator of how hot the surface of the star is.
a. surface of our yellow sun is about 6,000 degrees celsius
b. surface of hottest (blue-white) stars is about 50,000 degrees celsius
c. surface of the coolest (red) stars is about 3,000 degress celsius
2. The core of a star is much hotter than the surface. The core of our sun is about 15,000,000 degrees celsius