Dwarf planet gets new name

Astronomers give "Xena" a permanent name and add Pluto to a catalog of small bodies.
By | Published: September 14, 2006 | Last updated on May 18, 2023
Eris and its moon Dysnomia
Eris and its moon Dysnomia, illustrated here, sparked squabbles among astronomers much like their mythological namesakes.
Francis Reddy
September 14, 2006
The trouble-making object that forced astronomers to reconsider Pluto’s planetary status has finally received its official name — Eris.

The name, taken from a Greek goddess of discord and strife, was “too perfect to resist,” says Eris discoverer Michael Brown of Caltech. It was the January 2005 discovery of Eris — better known by its TV-inspired nickname, Xena — that put Pluto’s demotion on a fast track. Eris is about 5-percent bigger than Pluto.

Eris at a glance
The International Astronomical Union (IAU) put a hold on naming Eris until scientists could define what a planet is — and determine whether both objects or neither qualified. Following contentious discussions, the world’s astronomers voted August 24 to classify both objects as “dwarf planets.”

On September 7, astronomers at the IAU’s Minor Planet Center (MPC) in Cambridge, Massachusetts, added Pluto and Eris to its catalog. Pluto received number 134340, while Eris is 136199. The MPC is the official organization responsible for collecting orbital and physical data on all of the solar system’s small bodies.

Until last week, Pluto had been the only Sun-obiting, non-cometary body in the MPC’s scope not given a minor-planet number.

On Wednesday, astronomers announced names for Eris and its moon, now called Dysnomia. The mythological Eris provoked a squabble among Greek goddesses that ignited the Trojan War. Her daughter Dysnomia was the spirit of lawlessness.

Brown and his colleagues intended Xena only as a shorthand for Eris’ unwieldy temporary designation of 2003 UB313. The name comes from the fictional heroine of TV’s Xena: Warrior Princess.

Brown admits the object’s new name will take some getting used to. “I’ll miss Xena, but her spirit lives on,” he says with a smile. Dysnomia, the essence of lawlessness, is a nod to actress Lucy Lawless, who played Xena in the TV series.