Eris (Xena): Our Solar System

Discovery images of the dwarf planet Eris. The three images were taken 1 1/2 hours apart on the night of October 21st, 2003. Eris can be seen very slowly moving across the sky over the course of 3 hours. Eris was discovered in July, 2005 by Mike Brown of CalTech and his team. Eris was originally named Xena or UB313 but re-named Eris by the IAU (International Astronomical Union). On 10th September 2005, astronomers at the Keck Observatory took a look at Eris with a new instrument that allows them to see details as precise as those seen from the Hubble Space Telescope. The images quickly revealed that it has a faint moon in orbit around it! They named Eris’ moon Dysnomia, the daughter of the god Eris. In 2008, they named Eris, including Pluto, Sedna and Ceres, Dwarf Planets or Plutoids. Eris is the 10th planet and is the most distant object that orbits the sun in the frozen fringes of the Kuiper Belt. Approximately 10 billion miles from the sun, this is more than 3 times further than the next closest plutoid, Pluto.

Eris also takes double the time to orbit the sun than Pluto. Approximately 557 Earth years is equal to 1 Eris year. Eris has a diameter between 2,400 and 3,000 km. Eris plays a big part in our Solar System and is important to us because it is the largest object and the largest dwarf planet to be found orbiting the sun since 1846, when Neptune and its moon Triton was discovered. In conclusion, Eris is the 10th planet in our solar system and is rocky unlike many planets before it.

References:

• Dwarf Planets; UB313 or Eris http://sse.jpl.nasa.gov/planets/profile.cfm?Object=Dwarf&Display=OverviewLong#eris

• The Discovery of Eris, the largest known dwarf planet. http://www.gps.caltech.edu/~mbrown/planetlila/

• Eris-a dwarf planet
http://www.windows.ucar.edu/tour/link=/our_solar_system/dwarf_planets/eris.html&edu=high