Group X Dwarf Planets

Dwarf Planets

A dwarf planet an object that is neither a planet nor a natural satellite.
Dwarf planets are too small to be actual planets and they have to have certain qualities it must have such as:Orbit the sun, has enough mass to assume a nearly round shape, has not cleared the neighborhood around its orbit and isn't a moon.


The main distinction between a dwarf planet and a planet is that planets have cleared the path around the sun while dwarf planets tend to orbit in zones of similar objects that can cross their path around the sun, such as the asteroid and Kuiper belts. Dwarf planets also are generally smaller than the planet Mercury.

The first five recognized dwarf planets are Ceres, Pluto, Eris, Makemake and Haumea. Scientists believe there may be dozens or even more than 100 dwarf planets awaiting discovery.

The IAU recognized Pluto's special place in our solar system by designating dwarf planets that orbit the sun beyond Neptune as plutoids. Eris, which orbits far beyond Neptune, is a Pluto while Ceres, which orbits in the main asteroid belt between Mars and Jupiter is a dwarf planet.

The largest dwarf planet in the solar system is Pluto followed by Eris, Makemake, Haumea, with the smallest being Ceres. The order of the dwarf planets from closest to Sun outwards is Ceres, Pluto, Haumea, Makemake, with Eris being the furthest from the Sun.

In 2006 the organization responsible for classifying celestial bodies, the International Astronomical Union, decided that a new class of objects was needed. The solar system's erratic ninth planet, Pluto, was assigned to the new 'dwarf planet' category along with four other bodies, all tinier than Earth’s moon. Some astronomers expect there may be as many as 50 dwarf planets in the solar system.

Pluto, discovered in 1930, orbits the sun at an average of 39.5 times the Earth’s distance. Its diameter is 1,430 miles (2,302 km). Pluto takes 247.9 Earth years to orbit the sun, and its day is 6.39 times as long as Earth’s. Pluto has five known moons: Charon, Nix, Hydra and two that were recently discovered and have not yet been named.

Haumea was discovered in 2003. This dwarf planet has an extremely elongated shape, with its longest dimension being about 1,218 miles long (1,960 km). Haumea rotates very rapidly and has the shortest day of all the dwarf planets, only 3.9 hours. Orbiting 43.1 times farther from the sun than Earth does, Haumea takes nearly 282 Earth years to complete one orbit. Haumea has two moons, Hi’iaka and Namaka.

Makemake, discovered in 2005, has no known moons. Makemake orbits at 45.3 times Earth’s distance and takes more than 305 years to complete a circuit of the sun. Its day is 22.5 hours. Makemake’s average diameter is 882 miles (1,420 km).

Ceres, first spotted by astronomers in 1801, was first called a planet and later an asteroid. In 2006 it was reclassified as a dwarf planet. Ceres is the closest dwarf planet to Earth, orbiting at only 2.8 times Earth’s distance from the sun. Its year takes 4.6 Earth years and its day is 9.1 hours. Ceres has no known moons.

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