Ceres

Ceres, catch taken with realist brightness
since SpaceEngine. 

Ceres is the fifth nearest planet to the Sun (the nearest dwarf planet), and it is the smallest planet in the solar system, it is also the only dwarf planet that isn't a TNO (Trans-Neptunian object) Its name comes from the roman deity Ceres.

Ceres is a Dwarf Planet (Cool Selena), located between Mars and Jupiter, in the main Asteroid Belt, it has a mass of 9.43 x 10^20 Kg and a diameter of 952.4 Km, therefore, its density is 2.07 g/cm³ (Approximately).

Although it is less massive planet, Ceres is the largest and most massive object in the Asteroid Belt (its mass represents a third of the total mass of the Asteroid Belt), this planet in the past was considered a asteroid, but it has a lot of mass to be an asteroid and it has very little mass to be a planet, so since 2006 the International Astronomical Union considers that Ceres is a Dwarf  Planet.

Its rotation period is 9.07 hours and its orbital period is 1682 days.  This planet doesn't have natural satellites, because it has little gravity (0,28 m/s² or 0,029 g on its surface).