Gravitationally rounded objects in the Solar System have a rounded, ellipsoidal shape due to the forces of their own gravity (hydrostatic equilibrium) and their sizes range from dwarf planets and moons to the planets and the sun. This list does not include any small Solar System bodies, but it does a sample of planetary-mass objects whose shape has yet to be accurately determined. The Sun's orbital characteristics are listed in relation to the Galactic Center, while all other objects are listed in order of their distance from the Sun.
The Sun is a G-type main-sequence star. It contains almost 99.9 percent of all the mass in the Solar System.
A planet is defined according to the 2006 International Astronomical Union (IAU) definition; as a body in orbit around the Sun that was large enough to have achieved hydrostatic equilibrium and to have cleared the neighbourhood around its orbit. The practical meaning of "cleared the neighborhood" is that a planet is comparatively massive enough for its gravitation to control the orbits of all objects in its vicinity. By the IAU's definition, there are eight planets in the Solar System; four terrestrial planets (Mercury, Venus, Earth and Mars) and four giant planets, which can be divided further into two gas giants (Jupiter and Saturn) and two ice giants (Uranus and Neptune). When excluding the Sun, the four giant planets account for more than 99 percent of the mass of the Solar System.
The IAU, the internationally recognized authority for assigning designations to celestial bodies, defines dwarf planets as bodies that are large enough to have achieved hydrostatic equilibrium, but have not cleared their neighbourhoods of similar objects. Since 2008, there have been five dwarf planets recognized by the IAU. Ceres orbits in the asteroid belt, between the orbits of Mars and Jupiter. The others orbit beyond Neptune and are subclassified as plutoids.