A
G-type main-sequence star (Spectral type: G-V), often (and imprecisely) called a
yellow dwarf, or
G dwarf star, is a
main-sequence star (luminosity class V) of
spectral type G. Such a star has about 0.8 to 1.2
solar masses and
surface temperature of between 5,300 and 6,000
K.
, Tables VII, VIII. Like other main-sequence stars, a G-type main-sequence star is in the process of converting the
element hydrogen to
helium in its core by means of
nuclear fusion. The
Sun, the star to which the Earth is gravitationally bound in the
Solar System and the object with the largest
Apparent magnitude, is an example of a G-type main-sequence star. Each second, the sun fuses approximately 600 million
tons of hydrogen to helium,
converting about 4 million tons of
matter to
energy. Besides the Sun, other well-known examples of G-type main-sequence stars include
Alpha Centauri A,
Tau Ceti, and
51 Pegasi.