1) As a main-sequence star, the Sun's hydrogen supply should : 1828912
1) As a main-sequence star, the Sun's hydrogen supply should last about 10 billion years from the zero-age main sequence until its evolution to the giant stages.
2) About 90% of the star's total life is spent on the main sequence.
3) Helium fusion requires a higher temperature than hydrogen fusion.
4) While more massive than most of its neighbors, our Sun is still technically a low-mass star.
5) The least massive red main-sequence stars may have lifetimes of a trillion years.
6) The main reason that stars evolved off the main sequence is because they are becoming less massive as energy is lost into space from the proton-proton cycle.
7) The initial rise off the main sequence in stage 8 comes from gravitational energy of the contracting helium core.
8) Paradoxically, while the core of the red giant is contracting and heating up, its radiation pressure causes its photosphere to swell up and cool off.
9) Once the helium flash occurs at stage 10, the star stabilizes again on the horizontal branch of the H-R diagram, but now hundreds of times as bright as on the main sequence.
10) The helium flash stage lasts several thousand years.