Solar System/Eris

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Eris (pronounced EAR-us or AIR-us) is the largest known dwarf planet in the solar system, with a diameter of about 2500 kilometers and a mass that is 27% greater than Pluto's. It was first spotted in January 2005. Eris's orbit is beyond the Kuiper belt.

Classification[edit]

Since Eris orbits beyond the orbit of Neptune, it is a trans-Neptunian object. Since it is a trans-Neptunian dwarf planet, it is a plutoid.

Orbit[edit]

It takes Eris 557 years to orbit the sun. The orbit is highly elliptical, with an aphelion 97.5 AU from the Sun but a perihelion only 37.9 AU from the Sun. Its orbit is tilted by 44° relative to Earth's orbit.

Physical characteristics[edit]

Methane is known to be present on Eris.

Satellite[edit]

Eris has only one known moon, Dysnomia, which has an estimated diameter of between 100 and 250 kilometers.