Solar System
The principal component of the Solar System is the Sun, a G2 main-sequence star that contains 99.86% of the system's known mass and dominates it gravitationally. The Sun's four largest orbiting bodies, the giant planets, account for 99% of the remaining mass, with Jupiter and Saturn together comprising more than 90%. The remaining objects of the Solar System (including the four terrestrial planets, the dwarf planets, moons, asteroids, and comets) together comprise less than 0.002% of the Solar System's total mass.
Celestial coordinate system
The heliocentric ecliptic system describes the planets' orbital movement around the Sun, and centers on the barycenter of the solar system (i.e. very close to the center of the Sun). The system is primarily used for computing the positions of planets and other solar system bodies, as well as defining their orbital elements.