Gridr (moon)

Gridr (Saturn LIV), originally known as S/2004 S 20, 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 March 22, 2007.^[3] It was given its permanent designation in June 2021.^[4] On 24 August 2022, it was officially named after Gríðr, a jötunn in Norse mythology.^[5] She is the mother of Víðarr the silent and the consort of Odin. She warned Thor about the treachery of Geirröðr and equipped him with her belt of strength, her iron glove, and her staff Gríðarvöl (Gríðr's-staff).^[6]

Gridr

Discovery[1]
Discovered by	Sheppard et al.
Discovery date	2019
Designations
Named after	Gríðr
Alternative names	Saturn LIV S/2004 S 20 S2423b[2]
Orbital characteristics[2]
Semi-major axis	19211000 km
Eccentricity	0.204
Orbital period (sidereal)	−990.23 days
Inclination	163.1°
Satellite of	Saturn
Group	Norse group
Physical characteristics
Mean diameter	4 km
Apparent magnitude	25.0

Gridr is about 4 kilometres in diameter, and orbits Saturn at an average distance of 19.418 Gm in 1010.55 days, at an inclination of 163° to the ecliptic, in a retrograde direction and with an eccentricity of 0.197.^[3]