when does a star leave the main sequence
Main sequence In general, the more massive a star is, the shorter its lifespan on the main sequence. After the hydrogen fuel at the core has been consumed, the star evolves away from the main sequence on the HR diagram. The behavior of a star now depends on its mass, with stars below 0.23 M☉ becoming white dwarfs directly, whereas stars with up to ten solar masses pass through a red giant stage.[3] More massive stars can explode as a supernova,[4] or collapse directly into a black hole.
G-type main-sequence star 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 0.84 to 1.15 solar masses and surface temperature of between 5,300 and 6,000 K.[2], Tables VII, VIII. Like other main-sequence stars, a G-type main-sequence star is converting the element hydrogen to helium in its core by means of nuclear fusion.[3] 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(G2V type). Each second, the Sun fuses approximately 600 million tons of hydrogen to helium, converting about 4 million tons of matter to energy.[4][5] Besides the Sun, other well-known examples of G-type main-sequence stars include Alpha Centauri A, Tau Ceti, and 51 Pegasi.[6][7][8]