S/2004 S 21

S/2004 S 21
Discovery
Discovered by	Sheppard et al.
Discovery date	2019
Designations
Alternative names	S5602a
Orbital characteristics
Semi-major axis	23810400 km
Eccentricity	0.312
Orbital period (sidereal)	−1365.1 days
Inclination	154.6°
Satellite of	Saturn
Group	Norse group
Physical characteristics
Mean diameter	3 km
Apparent magnitude	25.4

S/2004 S 21 is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019 from observations taken between December 12, 2004 and January 17, 2007.^[3]

S/2004 S 21 is about 3 kilometres in diameter, and orbits Saturn at an average distance of 22.645 Gm in 1272.61 days, at an inclination of 160° to the ecliptic, in a retrograde direction and with an eccentricity of 0.318.^[3]

References

^ Discovery Circumstances from JPL
^ ^a ^b S.S. Sheppard (2019). "Moons of Saturn, Carnegie Science, on line".
^ ^a ^b "MPEC 2019-T127 : S/2004 S 21". minorplanetcenter.net. Retrieved 7 October 2019.

Zdroj:https://en.wikipedia.org?pojem=S/2004_S_21
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[Discoverers_JPL-1] Discovery Circumstances from JPL

[SheppardMoons-2] S.S. Sheppard (2019). "Moons of Saturn, Carnegie Science, on line".

[announcement-3] "MPEC 2019-T127 : S/2004 S 21". minorplanetcenter.net. Retrieved 7 October 2019.

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Related	Fiction The Day the Earth Smiled In Saturn's Rings (2018 documentary)
Category

Discovery^[1]
Discovered by	Sheppard et al.
Discovery date	2019
Designations
Alternative names	S5602a^[2]
Orbital characteristics^[2]
Semi-major axis	23810400 km
Eccentricity	0.312
Orbital period (sidereal)	−1365.1 days
Inclination	154.6°
Satellite of	Saturn
Group	Norse group
Physical characteristics
Mean diameter	3 km
Apparent magnitude	25.4