S/2019 S 1

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S/2019 S 1
S/2019 S 1 on the day of its discovery, revealed by stacking multiple images to its motion
Discovered byE. Ashton et al.
Discovery date2019 (announced 2021)
Orbital characteristics[1]
11221100 km
443.78 days
Satellite ofSaturn
GroupInuit group (Kiviuq)[3][2]
Physical characteristics
Mean diameter

S/2019 S 1 is a natural satellite of Saturn. Its discovery was announced by Edward Ashton, Brett J. Gladman, Jean-Marc Petit, and Mike Alexandersen on 16 November 2021 from Canada–France–Hawaii Telescope observations taken between 1 July 2019 and 14 June 2021.[1]

Apparent path of S/2019 S 1 as seen from Earth during 2019–2021. Colored circles along the path mark the dates and locations at which the moon was observed.

S/2019 S 1 is about 5 kilometres in diameter, and orbits Saturn at an average distance of 11.2 million km (7.0 million mi) in 443.78 days, at an inclination of 44° to the ecliptic, in a prograde direction and with an eccentricity of 0.623.[1] It belongs to the Inuit group of prograde irregular satellites, and is among the innermost irregular satellites of Saturn.[3] It might be a collisional fragment of Kiviuq and Ijiraq, which share very similar orbital elements.[4]

This moon's eccentric orbit takes it closer than 1.5 million km (0.93 million mi) to Iapetus several times per millennium.[4]


  1. ^ a b c d "MPEC 2021-W14 : S/2019 S 1". minorplanetcenter.net. Retrieved 16 November 2021.
  2. ^ a b Ashton, Edward; Gladman, Brett; Beaudoin, Matthew; Alexandersen, Mike; Petit, Jean-Marc (May 2022). "Discovery of the Closest Saturnian Irregular Moon, S/2019 S 1, and Implications for the Direct/Retrograde Satellite Ratio". The Astronomical Journal. 3 (5): 5. Bibcode:2022PSJ.....3..107A. doi:10.3847/PSJ/ac64a2. S2CID 248771843. 107.
  3. ^ a b Ashton, Edward; Gladman, Brett; Beaudoin, Matthew; Alexandersen, Mike; Petit, Jean-Marc (October 2021). Detection biases favour retrograde over direct irregular moons. 53rd Annual DPS Meeting. American Astronomical Society. 308.09. Retrieved 17 November 2021.
  4. ^ a b S/2019 S 1: Tilmann Denk