| Greip | |
| Mpc Name: | Saturn LI |
| Alt Names: | S/2006 S 4 |
| Discovered: | 2006 |
| Discoverer: | Scott S. Sheppard David C. Jewitt Jan T. Kleyna Brian G. Marsden |
| Named After: | Greipa |
| Orbit Ref: | [1] |
| Inclination: | 179.8° |
| Eccentricity: | 0.326 |
| Period: | −921.2 days |
| Satellite Of: | Saturn |
| Group: | Norse group |
| Rotation: | ? h |
| Albedo: | 0.06 (assumed) |
| Magnitude: | 24.4 |
| Abs Magnitude: | 15.4 |
Greip or Saturn LI is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, Jan Kleyna, and Brian G. Marsden on 26 June 2006, from observations taken between 5 January and 1 May 2006. Greip is about 5 kilometres in diameter, and orbits Saturn at an average distance of 18,066 Mm in 906.556 days, at an inclination of 172.7° to the ecliptic (159.2° to Saturn's equator), in a retrograde direction and with an eccentricity of 0.3735, and is presumably at high risk of eventually colliding with Phoebe.[2] It is unknown whether Greip is more similar to Suttungr or Hyrrokkin in color.[2] Its rotation period is most likely hours with two minima in the light curve,[3] but a longer period of 19 hours cannot be ruled out due to the short observation time by Cassini–Huygens.[2]
It is named after Greip, a giantess in Norse mythology.