Gridr (moon)

Moon of Saturn

GridrDiscovery[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+50%
−30% km

Apparent magnitude

| 25.0

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 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]

## References

[edit]

1. ^ Discovery Circumstances from JPL
2. ^ a b S.S. Sheppard (2019), Moons of Saturn, Carnegie Science, on line
3. ^ a b "MPEC 2019-T126 : S/2004 S 20". minorplanetcenter.net. Retrieved 7 October 2019.
4. ^ "M.P.C. 132212" (PDF). Minor Planet Center. International Astronomical Union. 1 June 2021. Retrieved 16 June 2021.
5. ^ "Names Approved for 10 Small Satellites of Saturn". usgs.gov. USGS. 24 August 2022. Retrieved 30 August 2022.
6. ^ Lindow, John (2002). Norse Mythology: A Guide to Gods, Heroes, Rituals, and Beliefs. Oxford University Press. p. 149\. ISBN 978-0-19-983969-8.

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Moons of Saturn

Listed in approximate increasing distance from Saturn

Ring moonlets|

* S/2009 S 1
* Aegaeon

Ring shepherds|

* Pan
* Daphnis
* Prometheus
* Epimetheus
* Janus

Other inner moons|

* Atlas
* Pandora

Alkyonides|

* Methone
* Anthe
* Pallene

Large moons
(with trojans)|

* Mimas
* Enceladus
* Tethys
* Telesto
* Calypso
* Dione
* Helene
* Polydeuces
* Rhea
* Titan
* Hyperion
* Iapetus

Inuit group (13)|

| Kiviuq subgroup|

* S/2019 S 1
* Kiviuq
* S/2005 S 4
* S/2020 S 1
* Ijiraq

|

Paaliaq subgroup|

* Paaliaq

Siarnaq subgroup|

* S/2004 S 31
* Tarqeq
* S/2019 S 14
* Siarnaq
* S/2020 S 3
* S/2019 S 6
* S/2020 S 5

Gallic group (7)|

* Albiorix
* Bebhionn
* S/2007 S 8
* Saturn LX
* Erriapus
* Tarvos
* S/2020 S 4

Norse group (100)|

| Phoebe subgroup|

* Phoebe
* S/2006 S 20
* S/2006 S 9

|

* Skathi
* S/2007 S 5
* S/2007 S 7
* S/2007 S 2
* S/2004 S 37
* S/2004 S 47
* S/2004 S 40
* S/2019 S 2
* S/2019 S 3
* S/2020 S 7
* Skoll
* S/2020 S 2
* S/2019 S 4
* S/2004 S 41
* S/2004 S 42
* Hyrrokkin
* Greip
* S/2004 S 13
* S/2007 S 6
* Mundilfari
* S/2006 S 1
* S/2004 S 43
* S/2006 S 10
* S/2019 S 5
* Gridr
* Bergelmir
* Jarnsaxa
* Narvi
* Suttungr
* S/2004 S 44
* S/2007 S 3
* S/2004 S 45
* Hati
* S/2004 S 17
* S/2006 S 11
* S/2004 S 12
* Eggther
* S/2006 S 13
* S/2007 S 9
* S/2019 S 7
* S/2019 S 8
* Farbauti
* Thrymr
* Bestla
* S/2019 S 9
* S/2004 S 46
* Angrboda
* S/2019 S 11
* Aegir
* S/2019 S 10
* Beli
* S/2019 S 12
* Gerd
* S/2019 S 13
* S/2006 S 14
* Gunnlod
* S/2019 S 15
* S/2020 S 6
* S/2004 S 7
* S/2006 S 3
* S/2005 S 5
* Skrymir
* S/2006 S 16
* S/2006 S 15
* S/2004 S 28
* S/2020 S 8
* Alvaldi
* Kari
* S/2004 S 48
* Geirrod
* Fenrir
* S/2004 S 50
* S/2006 S 17
* S/2004 S 49
* S/2019 S 17
* Surtur
* S/2006 S 18
* Loge
* Ymir
* S/2019 S 19
* S/2019 S 18
* S/2004 S 21
* S/2004 S 39
* S/2019 S 16
* S/2004 S 53
* S/2004 S 36
* Thiazzi
* S/2019 S 20
* S/2006 S 19
* Saturn LXIV
* Fornjot
* S/2004 S 51
* S/2020 S 10
* S/2020 S 9
* Saturn LVIII
* S/2019 S 21
* S/2004 S 52

Outlier prograde
irregular moons|

* S/2006 S 12
* S/2004 S 24

* Rings of Saturn
* Cassini–Huygens
* Chiron
* Chrysalis
* Themis
* S/2004 S 3
* S/2004 S 4
* S/2004 S 6
* Peggy
* Bleriot
* Moonlet
* In fiction

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Saturn

* Outline

Geography|

* Dragon Storm
* Great White Spot
* Saturn Electrostatic Discharges
* Hexagon
* Magnetosphere
* Rings

Moons|

* S/2009 S 1
* Ring moonlets
* Pan
* Daphnis
* Atlas
* Prometheus
* Pandora
* Epimetheus
* Janus
* Aegaeon
* Mimas
* Methone
* Anthe
* Pallene
* Enceladus
* Tethys
* Telesto
* Calypso
* Dione
* Helene
* Polydeuces
* Rhea
* Titan
* Hyperion
* Iapetus
* Inuit group
* Kiviuq
* Paaliaq
* Siarnaq
* Gallic group
* Albiorix
* Norse group
* Phoebe

Astronomy|

* Delta Octantis
* Saturn-crossing minor planets
* Solar eclipses on Saturn

Exploration|

* Cassini–Huygens (Huygens)
* timeline
* retirement
* Pioneer 11
* Voyager program
* Voyager 1
* Voyager 2

Related|

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

* Category

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