G2V

G2V is a stellar classification in the Morgan–Keenan (MK) system that denotes a Sun-like, main-sequence star. The G indicates a surface temperature in the approximate range of 5,300–6,000 K and a yellow-white color; the numeral 2 is a subclass within G, signaling it is somewhat cooler than the middle of the G range. The Roman numeral V designates the star as a main-sequence star, fusing hydrogen in its core. The Sun is the best-known example of a G2V star.

Typical properties of G2V stars are very close to those of the Sun: effective temperature around 5,500–6,000 K, a radius about 0.9–1.2 times that of the Sun, a mass roughly 0.8–1.2 solar masses, and a luminosity near that of the Sun. Their spectra show prominent hydrogen Balmer lines and metal lines, and they generally exhibit solar-type magnetic activity.

G2V stars have long, stable main-sequence lifetimes, generally on the order of about 10 billion years, depending on mass and chemical composition. The classification is widely used in stellar catalogs to compare Sun-like stars for studies of stellar evolution, exoplanets, and galactic stellar populations.