Changes

Finally the [[International Astronomical Union]] declared<ref>"[http://www.iau.org/iau0602.423.0.html IAU0602: the Final IAU Resolution on the Definition of 'Planet' Ready for Voting]," ''International Astronomical Union'', 2005. Accessed January 14, 2008.</ref> that Pluto and 2003 UB₃₁₃ were not planets, but belonged to a new category called [[dwarf planet]]s. Then on September 6, 2006, Mike Brown and his team<ref name=Brown4>Brown, Mike. "[http://www.gps.caltech.edu/%7Embrown/planetlila/index.html The discovery of Eris, the largest known dwarf planet]." California Institute of Technology. Accessed January 22, 2008.</ref> recognized that the name "Xena" was inappropriate for 2003 UB₃₁₃ and suggested to the IAU that they name it Eris, after the Greek goddess of discord and strife. They also suggested that the IAU name the satellite Dysnomia, for the Greek goddess of lawlessness and daughter of Eris.<ref>Dysnomia, meaning "lawlessness," is also a play on the name of the American actress who portrayed Xena, Lucy Lawless.</ref> Four days later, the IAU oficially named the primary Eris and named its satellite Dysnomia.<ref name=IAU1>[http://cfa-www.harvard.edu/iau/special/08747.pdf IAU Circular No. 8747], International Astronomical Union, September 10, 2006. Accessed May 15, 2008.</ref><ref>Brown</ref>

Finally the [[International Astronomical Union]] declared<ref>"[http://www.iau.org/iau0602.423.0.html IAU0602: the Final IAU Resolution on the Definition of 'Planet' Ready for Voting]," ''International Astronomical Union'', 2005. Accessed January 14, 2008.</ref> that Pluto and 2003 UB₃₁₃ were not planets, but belonged to a new category called [[dwarf planet]]s. Then on September 6, 2006, Mike Brown and his team<ref name=Brown4>Brown, Mike. "[http://www.gps.caltech.edu/%7Embrown/planetlila/index.html The discovery of Eris, the largest known dwarf planet]." California Institute of Technology. Accessed January 22, 2008.</ref> recognized that the name "Xena" was inappropriate for 2003 UB₃₁₃ and suggested to the IAU that they name it Eris, after the Greek goddess of discord and strife. They also suggested that the IAU name the satellite Dysnomia, for the Greek goddess of lawlessness and daughter of Eris.<ref>Dysnomia, meaning "lawlessness," is also a play on the name of the American actress who portrayed Xena, Lucy Lawless.</ref> Four days later, the IAU oficially named the primary Eris and named its satellite Dysnomia.<ref name=IAU1>[http://cfa-www.harvard.edu/iau/special/08747.pdf IAU Circular No. 8747], International Astronomical Union, September 10, 2006. Accessed May 15, 2008.</ref><ref>Brown</ref>

[[Image:ErisDysnomiaConcept.jpg|thumb|250px|left|Artist's conception of Eris and Dysnomia. The bright object in the upper left of the image is the [[Sun]].]]

[[Image:ErisDysnomiaConcept.jpg|thumb|250px|left|Artist's conception of Eris and Dysnomia. Dysnomia lies slightly above and to the left of Eris. The bright object in the upper left of the image is the [[Sun]].]]

 

== Orbital characteristics ==

== Orbital characteristics ==

Dysnomia orbits Eris in a nearly circular orbit with a sidereal period of 15.774 days and a semi-major axis of 37,350 km. From these properties, Brown and Schaller were able to calculate Eris' mass.<ref name=Brown1/>

Dysnomia orbits Eris in a nearly circular orbit with a sidereal period of 15.774 days and a semi-major axis of 37,350 km. From these properties, Brown and Schaller were able to calculate Eris' mass.<ref name=Brown1/>