The color of a star is a function of its temperature.
For example:
1- If a star looks red that means that its temperature is approximately 2,500 Kelvin.
2- Our Sun, which actually looks white from space, measures about 6,000 Kelvin.
3- The hotter the star, the further up the spectrum you go. The hottest stars are the blue ones. A star appears blue once its surface temperature goes above 10,000 Kelvin or so, a star will appear blue to our eyes.
Just a fact: The hottest star known in the Universe are the blue hypergiant stars. These are stars with more than 100 times mass of the Sun. One of the best known examples is ''Eta Carinae'' that is located about 7,500 light-years from the Sun. ''Eta Carinae'' could be as large as 180 times the radius of the Sun, and its surface is 36,000 - 40,000 Kelvin.
Well hope i helped! I f you need anything more ask me! And think about Eta Carinae is super hot, like wow, 40,000 Kelvin is like 79,000 degrees F. So thats hot, like no joke is super hot.
