White stars are hotter than red and yellow. Blue stars are the hottest stars of all. Stars are not really star-shaped. They are round like our sun.
Red stars are cooler than the sun, with surface temperatures of 3,500 K for a bright red star and 2,500 K for a dark red star. The hottest stars are blue, with their surface temperatures falling anywhere between 10,000 K and 50,000 K.
