The sun contains 99.9% of the matter in the entire Milky Way solar system.

Our solar system, located in the Milky Way galaxy, is a mostly empty,
flattened disk of space. Our solar system contains the sun, planets,
satellites and rings of planets, asteroids, comets and other dust
particles. The sun contains 99.9% of the matter in the solar system, the
rest make up the remaining 0.1%. This is why the sun has strong gravity and
planets remain in their orbits.