Sol

Sol is a solar system, as well as the name of the Solar System's star, which is by far its chief component. Its large mass (332,900 Earth masses) produces temperatures and densities in its core high enough to sustain nuclear fusion, which releases enormous amounts of energy, mostly radiated into space as electromagnetic radiation, peaking in the 400–700 nm band of visible light.

Sol is a type G2 main-sequence star. Its position on the main sequence puts it in the “prime of life” for a star, not yet having exhausted its store of hydrogen for nuclear fusion. The Sun is growing brighter; early in its history its brightness was 70% that of what it is today.

Sol is a population I star; it was born in the later stages of the universe’s evolution and thus contains more elements heavier than hydrogen and helium metals (in astronomical parlance) than the older population II stars. This high metallicity is thought to have been crucial to the Sol's development of a planetary system because the planets form from the accretion of “metals”.

Humans are its original sentient inhabitants, and their chief political body is the Earth Republic. Species with artificial sentience, and limited immigration of other sentient species has since diversified the solar system's population.