Question

why doesn't the sun appear blue

Answer 1

The answer is hidden in the Wein's law, which says the wavelength at which the intensity of emitted radiation peaks, is inversely proportional to the Absolute Temperature of the body. In case of sun, the wavelength peaks approximately around 519 nm, which corresponds to Yellow colour, and hence sun appears yellow, not blue. 

Typically, the mass of the star usually determines its colour. The more massive the star is, the more inward acting gravitational force, and the more the core needs to fuse hydrogen to compensate the increasing gravitational force. and hence the hotter star becomes. That corresponds to peaks in higher frequencies of radiation