New Satellite Moon of Saturn S/2003 S1

Saturn's New Satellite S/2003 S1


University of Hawaii astronomers announce the discovery of the first new satellite of Saturn in nearly 3 years. This brings the total number of Saturnian satellites to 31.


The new satellite was discovered on February 5, 2003 by Scott S. Sheppard and David C. Jewitt along with Jan Kleyna. It was found using the world's biggest telescope/wide-field digital camera combination at the Subaru (8.3 meter diameter) telescope atop Mauna Kea in Hawaii. Recoveries were performed at the University of Hawaii 2.2 meter in 2003 and by David Donovan at the Subaru telescope in February 2004. Brian Marsden of the Harvard-Smithsonian Center for Astrophysics performed the orbit fit for the new satellite.

The satellite was formally announced by the International Astronomical Union on April 8, 2003. S/2003 S1 is classified as an irregular satellite of which Saturn now has 14 known. It has an eccentric distant retrograde orbit (ie. its orbital rotation is opposite to Saturn's rotation). Fifty irregular satellites are known at Jupiter of which the majority have been discovered in the last 3 years (see New Jupiter Satellites discovered in 2003 ). Assuming that it reflects about 4% of the light that hits it from the Sun, the new satellite is about 8 km (5 miles) in diameter.

Figure 1: Discovery images of S/2003 S1 showing the motion of the satellite relative to background stars and galaxies. Click on the movie to learn more about the images.


See a table of Saturn's known satellites .

To learn more about our discovery of Jupiter satellites visit The Jupiter Satellite Page.

Scott S. Sheppard