Information on the irregular satellite system of Uranus

Until 1997, Uranus was alone among the outer planets in not having any know irregular satelltes. Irregular satellites are those whose orbits are either very non-circular or very inclined with respect to the equatorial plane of the planet; they also tend to be (although is not required) very distant from the planet. Since 1997, our team has discovered all known irregular satellites of this planet, and we hope that these web pages will serve to assist those looking for further information.

Announcement of a sixth irregular uranian satellite. (Oct. 1/2002)


Discovery in 1999 of three additional satellites.

Recovery! of all five satellites in summer 2000.

English story (Sept. 20/99).

Texte en francais (French story) (21 sept. 99).

Discovery in 1997 of the first 2 irregular uranian satellites.

Links from 1997

List of team members

Technical information

All known astrometry of 1999 U1, U2, and U3 (MPC format, last update 15 Jan/2001)

Bibliographic references
Data on orbital parameters (Courtesy ProjectPluto)
Data on orbital parameters (Courtesy JPL, note: mean, not osculating) (
Data on physical parameters (preliminary)
Orbit extrapolation (.ps)

Page maintained by:
Brett Gladman 
Observatoire de la Cote d'Azur

Cette page a été visitée fois depuis le 27 septembre 1999

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