Dwarf planets are a category of celestial bodies that share some characteristics with planets but do not meet all the criteria required to be classified as full-fledged planets. According to the International Astronomical Union (IAU), a dwarf planet is an object that:

• • Orbits the Sun.
  • Is spherical in shape due to its own gravity.
  • Has not cleared its orbit of other debris.
  • Is not a satellite (i.e. it is not a moon).

They differ from full planets in that they do not dominate their orbital zones. Notable examples include Pluto, Eris, Haumea, Makemake, and Ceres (the only dwarf planet located in the asteroid belt between Mars and Jupiter). Each with unique characteristics and locations within the Solar System. Their study provides valuable insights into the diversity and formation of small bodies in our Solar System.

1. 1. Pluto

• • • Location: Located in the Kuiper Belt, a region beyond Neptune.
    • Size: About 2,377 km (1,478 miles) in diameter.
    • Composition: Composed of a mixture of rock and ice.
    • Atmosphere: Thin, composed primarily of nitrogen, with traces of methane and carbon monoxide.
    • Moons: Has five known moons, Nix, Hydra, Kerberos, Styx with Charon being the largest and closest. Charon is also the largest moon compared to its parent planet in the solar system.

1. 2. Eris

• • • Location: Situated in the scattered disk, a distant region of the Solar System.
    • Size: Approximately 2,326 km (1,445 miles) in diameter.
    • Composition: Likely composed of rock and ice.
    • Atmosphere: Thin and temporary, composed mostly of nitrogen. It might form a more substantial atmosphere as it approaches the Sun.
    • Moons: Has one known moon, Dysnomia.

1. 3. Haumea

• • • Location: Located in the Kuiper Belt.
    • Size: About 1,632 km (1,014 miles) in diameter (not a perfect sphere due to its fast rotation).
    • Composition: Composed of rock with a thick icy crust.
    • Atmosphere: Thin and temporary.
    • Moons: Has two known moons, Namaka and Hi’iaka.

1. 4. Makemake

• • • Location: In the Kuiper Belt.
    • Size: Approximately 1,434 km (891 miles) in diameter.
    • Composition: Composed of rock and ice.
    • Atmosphere: Very thin, primarily composed of methane.
    • Moons: Has one known moon, MK 2, which was discovered in 2016.

1. 5. Ceres

• • • Location: Located in the asteroid belt between Mars and Jupiter.
    • Size: About 940 km (584 miles) in diameter.
    • Composition: Contains a mix of rock and water ice, with possible subsurface liquid water.
    • Atmosphere: Very thin, with water vapor detected.
    • Moons: Has no known moons.