New Saturnian Satellites

Okay, over the next few weeks it will get very confusing as to how many moons there are of Saturn. So lets start from before today. Before Cassini, there were 31 satellites. Cassini discovered two moons between Mimas and Enceladus, another trojan of Dione, and three satellites near the F ring. That brings us to 37 satellites. Since this time, the three F-ring moons have not been recovered and thus have not been given names like the other three Cassini moons. So lets subtract them from the list, leaving us with 34 moons.

Now add 12. David Jewitt and Scott Sheppard, the most prolific satellite discoverers of all time, today announced the discovery of 12 more outer satellites of Saturn. From the release:

The satellites were discovered on December 12, 2004 using the wide-field SuprimeCam camera on the 8.2-meter diameter Subaru telescope on Mauna Kea. They were followed up in January, February and March 2005 using Subaru and the nearby 8-m diameter Gemini North telescope.

The satellites were formally announced by the International Astronomical Union on May 3, 2005. The orbital elements are given in Table 1. All but one (S/2004 S11) orbit Saturn in a direction opposite to the planet's spin. These retrograde orbits are a hallmark of an origin by capture. The new moons range in diameter from about 3 km to 7 km, assuming a surface albedo of 4%.

This brings the total to 46. Certainly more on the way...

The Following table provides some information on the newly discovered satellites, such as orbital information (borrowed from Scott Sheppard's site):

Name  Semimajor axis i e km Year
S/2004 S07 19800000 165.1 0.580 5 2004
S/2004 S08 22200000 168.0 0.213 5 2004
S/2004 S09 19800000 157.6 0.235 5 2004
S/2004 S10 19350000 167.0 0.241 5 2004
S/2004 S11 16950000 41.0 0.336 5 2004
S/2004 S12 19650000 164.0 0.401 5 2004
S/2004 S13 18450000 167.4 0.273 5 2004
S/2004 S14 19950000 162.7 0.292 5 2004
S/2004 S15 18750000 156.9 0.180 5 2004
S/2004 S16 22200000 163.0 0.135 5 2004
S/2004 S17 18600000 166.6 0.259 5 2004
S/2004 S18 19650000 147.4 0.795 5 2004