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.
Primary (astronomy)
The center of mass is the average position of all the objects weighed by mass. The Sun is so massive that the Solar System's barycenter lies very near the Sun's center. However, the gas giants are far enough from the Sun that the Solar System's barycenter can be outside the Sun, despite the Sun comprising most of the Solar System's mass.