The sun is classified as a G2V star, sometimes referred to as a yellow dwarf. It is a Population I star in its main sequence. Although called a yellow dwarf, the sun actually emits white light that is often skewed by Earth's atmosphere and interstellar dust.
Star spectral classes are O, B, A, F, G, K, M and L ordered from hottest to coolest. There are 10 types, from zero to nine, within each class -- the lower the number, the hotter the star. The G2 rating of the sun indicates a moderately hot star, relative to all other stars, at the hotter end of the G spectrum, 8,500 to 10,300 degrees Fahrenheit. Stars are also classified by size and power using Roman numerals I, II, III, IV and V, with lower numbers denoting larger, more powerful stars. As a V star, the sun is small and still in the middle of its life. Population I stars, such as the sun, are the youngest and smallest of the stars and contain the most metals.