PX158 - I2 - stellar classes
main-sequence
- star is fusing hydrogen in its core
- covers the majority of a star's lifetime:
- the sun will be in the main-sequence for
- using luminosity-temperature-radius of stars relation,
red giant
- after hydrogen in the core has depleted, helium fusion begins
- star expands and outer layers cool
- for the sun,
- a star will not spend much time in this phase
- for the sun, it will be about
white dwarf
- the end states of most main-sequence stars
- in an isolated state, they remain in this state