The spectral class of a star indicates its photospheric temperature, which (for main-sequence stars) correlates to overall mass. The appropriate spectral range for habitable stars is considered to be "late F" or "G", to "mid-K". This corresponds to temperatures of a little more than 7,000 K down to a little less than 4,000 K (6,700 °C to 3,700 °C); the Sun, a G2 star at 5,777 K, is well within these bounds. This spectral range probably accounts for between 5% and 10% of stars in the local Milky Way galaxy. "Middle-class" stars of this sort have a number of characteristics considered important to planetary habitability: