S/2009 S 1

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S/2009 S 1
PIA11665 moonlet in B Ring cropped.jpg
The bright dot with a long shadow is S/2009 S 1
Discovered byCassini Imaging Team
Discovery date2009
Orbital characteristics[2]
117000 km
Satellite ofSaturn
Grouppropeller moonlet
Physical characteristics
Mean diameter
0.3 km

S/2009 S 1 is a "propeller moonlet" of Saturn orbiting at a distance of 117,000 km (73,000 mi), in the outer part of the B Ring, and with a diameter of 300 m (1,000 ft).[3] The moonlet was discovered by the Cassini Imaging Team during the Cronian equinox event on 26 July 2009,[4] when it cast a shadow 36 km (22 mi) long onto the B Ring. S/2009 S 1 protrudes 150 m (500 ft) north of the ring.[5] The image was taken approximately 296,000 km (184,000 mi) from Saturn.[3]


A wider perspective of the image above. S/2009 S 1 is in the center. The Cassini Division is on the right.

S/2009 S 1 was first identified by the Cassini Imaging Team[4] on 26 July 2009. It was discovered during 2009's equinox by an approximately 36 kilometres (22 mi) long shadow that it cast on the planet Saturn's B ring. This particular moon is one of the smallest moons of Saturn.

See also[edit]


  1. ^ Discovery Circumstances from JPL
  2. ^ S.S. Sheppard (2019), Moons of Saturn, Carnegie Science, on line
  3. ^ a b "A Small Find Near Equinox". Cassini Solstice Mission. JPL/NASA. 7 August 2009. Retrieved 2012-01-02.
  4. ^ a b "Cassini Imaging Science Team". Cassini Imaging Central Laboratory for OPerationS. Retrieved 2012-01-02.
  5. ^ Porco, C. & the Cassini Imaging Team (2 November 2009). "S/2009 S1". IAU Circular. 9091. Retrieved 2012-01-02.