S/2004 S 12

S/2004 S 12

Discovery[1]
Discovered by	Scott S. Sheppard et al.
Discovery site	Mauna Kea Obs.
Discovery date	12 December 2004
Orbital characteristics[2]
Epoch 9 August 2022 (JD 2459800.5)
Observation arc	15.61 yr (5,703 days)
Semi-major axis	0.1327201 AU (19,855,000 km)
Eccentricity	0.3711930
Orbital period (sidereal)	–2.86 yr (–1044.50 d)
Mean anomaly	326.59167°
Mean motion	0° 20^m 40.789^s / day
Inclination	163.85743° (to ecliptic)
Longitude of ascending node	330.73760°
Argument of perihelion	111.13920°
Satellite of	Saturn
Group	Norse group
Physical characteristics
Mean diameter	≈5 km[3]
Albedo	0.04 (assumed)[3]
Apparent magnitude	24.8[3]
Absolute magnitude (H)	15.9[2]

S/2004 S 12 is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, Jan Kleyna, and Brian G. Marsden on 4 May 2005 from observations taken between 12 December 2004 and 9 March 2005.

S/2004 S 12 is about 5 kilometres in diameter, and orbits Saturn at an average distance of 19,855,000 kilometres in about 1,044 days, at an inclination of 163.9° to the ecliptic, in a retrograde direction and with an eccentricity of 0.371.^[2][4]

This moon was considered lost^[5] until its recovery was announced on 12 October 2022.^[2] (In 2021, it had also been found in Canada-France-Hawaii Telescope observations from 2019.)^[6]

References

1. Discovery Circumstances from JPL
2. "MPEC 2022-T128 : S/2004 S 12". Minor Planet Electronic Circular. Minor Planet Center. 12 October 2022. Retrieved 12 October 2022.
3. S.S. Sheppard (2019), Moons of Saturn, Carnegie Science, on line
4. Jacobson, R.A. (2007) SAT272 (2007-06-28). "Planetary Satellite Mean Orbital Parameters". JPL/NASA. Archived from the original on 2011-08-10. Retrieved 2008-01-20.
5. Jacobson, B.; Brozović, M.; Gladman, B.; Alexandersen, M.; Nicholson, P. D.; Veillet, C. (28 September 2012). "Irregular Satellites of the Outer Planets: Orbital Uncertainties and Astrometric Recoveries in 2009–2011". The Astronomical Journal. 144 (5): 132. Bibcode:2012AJ....144..132J. doi:10.1088/0004-6256/144/5/132. S2CID 123117568.
6. Ashton, Edward; Gladman, Brett; Beaudoin, Matthew (August 2021). "Evidence for a Recent Collision in Saturn's Irregular Moon Population". The Planetary Science Journal. 2 (4): 12. Bibcode:2021PSJ.....2..158A. doi:10.3847/PSJ/ac0979.

• Institute for Astronomy Saturn Satellite Data
• Jewitt's New Satellites of Saturn page
• MPEC 2005-J13: Twelve New Satellites of Saturn, 3 May 2005 (discovery and ephemeris)