Ceres

• Region: Asteroid Belt
  
  

• Diameter: 940 km
  
  

• Mass: 9.39 × 10²⁰ kg
  
  

• Orbit: 4.6 Earth years, semi-major axis ~2.77 AU, eccentricity 0.08
  
  

• Rotation: 9.07 hours
  
  

Surface & Geology:
Ceres has a mixture of rocky and icy surface materials. Notable features include Occator Crater, with bright spots of sodium carbonate, and Ahuna Mons, a cryovolcanic dome rising ~4 km above the surface. Its surface includes both older, heavily cratered regions and younger, smoother plains.

Atmosphere:
Ceres has a very thin, transient water vapor atmosphere, likely produced by sublimation from surface ice or cryovolcanic activity.

Internal Structure:
Ceres is differentiated, with a rocky core, icy mantle, and possible subsurface briny ocean. Estimates suggest the interior may retain liquid water below the crust, with enough salinity to remain liquid at very low temperatures.

Temperature:
Surface temperatures range from –105°C to –38°C, warmer than Kuiper Belt dwarf planets but still extremely cold.

Discovery:
Discovered in 1801 by Giuseppe Piazzi. It was initially classified as a planet, then an asteroid, and later reclassified as a dwarf planet in 2006.