G stars

A member of a class of stars to which the Sun belongs. The G-type stars on the main sequence have surface temperatures of 5,300-6,000 K and therefore appear yellow in color. G type giant stars (such as Capella) are almost 100-500 K colder than the corresponding main sequence stars. G type supergiants have temperatures of 4,500-5,500 K. The spectrum of early type G stars, such as the Sun (G2), is dominated by ionized lines of calcium (H and K lines, mainly) and neutral metals. In later type G stars the molecular bands of CH molecules and CN molecules become visible. The main sequence and giant stars have masses of ~ 1 solar mass, while the supergiants are of ~ 10 solar masses. The luminosities of G-type giants are almost 30-60 times greater than that of the Sun, whereas the supergiants are 10,000-30,000 times more luminous.