Tracking of S/2001 U 1

A sixth irregular satellite of Uranus has been announced in October 2002,
following its discovery in 2001 and tracking around the planet.

Discovery announcement

The satellite was first identified by M. Holman and J. Kavelaars using data taken in August 2001 using the Cerro Telolo 4m Blanco telescope. Tracking of this satellite was extremely difficult due to its faint magnitude. After discovery, this satellite was located and measured by B. Gladman using images taken :

in Sept 2001 using the Palomar 5-meter telescope,
by P. Nicholson (Cornell University) and C. Dumas (JPL)

in Nov 2001 using the ESO VLT UT-3 8-meter telescope
by J-M. Petit (Observatoire de Besancon)

and
in Sept 2002 using the ESO VLT UT-3 8-meter telescope
by observers P.Rousselot and O. Mousis (Observatoire de Besancon)

An image from this final run, when the satellite was only a few arcminutes from the planet, is shown below. The quality of the ESO 8-m telescopes, allowing such a faint target to be seen so close to a bright planet in a single image is an impressive feat.

Using this information, M. Holman and T. Grav were able to recover the satellite in an additional August 2002 image from CTIO.

All available astrometry can be found on Minor Planet Electronic Circular 2002-S64 which contains an orbit computed by B. Marsden (CfA) whose orbits computations allowed the 2002 recovery.

Recovery Images

small S/2001 U 1 False-colour image of S/2001 U 1

Black and white image of S/2001 U 1 (negative image)

Brett Gladman's home page (UBC).
The uranian irregulars home page.