Hyrrokkin (moon)

Hyrrokkin
Discovery
Hyrrokkin imaged by the Cassini spacecraft in March 2013
Discovered by	Scott S. Sheppard David C. Jewitt Jan T. Kleyna Brian G. Marsden
Discovery date	December 2004
Designations
Designation	Saturn XLIV
Alternative names	S/2004 S 19
Orbital characteristics ^[1]
Semi-major axis	18437000 km
Eccentricity	0.333
Orbital period	−931.8 days
Inclination	151.4°
Satellite of	Saturn
Group	Norse group
Physical characteristics
Mean diameter	8+50% −30% km^[2]
Rotation period	12.76±0.03 h^[2]
Apparent magnitude	23.5

Hyrrokkin /hɪˈrɒkən/ or Saturn XLIV is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, Jan Kleyna, and Brian G. Marsden on June 26, 2006, from observations taken between December 12, 2004, and April 30, 2006.

Hyrrokkin is about 8 kilometres in diameter,^[3] and orbits Saturn at an average distance of 18,168 Mm in 914 days, at an inclination of 153° to the ecliptic (154° to Saturn's equator), in a retrograde direction and with an eccentricity of 0.3582. During four observations in March 2013, the synodic rotational period was measured by the Cassini spacecraft to approximately 12 hours and 45 minutes. The rotation period was later refined to 12.76±0.03 hours.^[2]

It was named in April 2007 after Hyrrokkin, a giantess from Norse mythology, who launched Hringhorni, Baldr's funeral ship. It was originally listed as being spelled Hyrokkin, but the spelling was later corrected.

References[]

^ S.S. Sheppard (2019), Moons of Saturn, Carnegie Science, on line
^ ^a ^b ^c Denk, T.; Mottola, S. (2019). Cassini Observations of Saturn's Irregular Moons (PDF). 50th Lunar and Planetary Science Conference. Lunar and Planetary Institute.
^ Rehnberg, Morgan (14 August 2015). "Cassini studies backwards-orbiting moon Hyrrokkin". Space Exploration Network. SEN. Retrieved 2015-08-17.

External links[]

Scott Sheppard's Saturnian satellites page
IAUC 8727: Satellites of Saturn June 30, 2006 (discovery)
MPEC 2006-M44: S/2004 S 19 June 26, 2006 (discovery and ephemeris)
IAUC 8826: Satellites of Jupiter and Saturn April 5, 2007 (Naming the moon)
IAUC 8860: Saturn XLIV (Hyrrokkin) July 31, 2007 (correcting the name)
Denk, T., Mottola, S. (2013): Irregular Saturnian Moon Lightcurves from Cassini-ISS Observations: Update. Abstract 406.08, DPS conference 2013, Denver (Colorado), October 10, 2013 (synodic rotation period)

v t Saturn
Outline of Saturn
Geography	Dragon Storm Great White Spot Hexagon Magnetosphere Rings
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Astronomy	Delta Octantis Saturn-crossing minor planets
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)

v t Natural satellites of the Solar System
Planetary satellites of	Earth Mars Jupiter Saturn Uranus Neptune
Dwarf planet satellites of	Orcus Pluto Haumea Quaoar Makemake Gonggong Eris
Minor-planet moons	· Near-Earth: Florence Didymos (Dimorphos) Moshup (Squannit) 1994 CC 2001 SN₂₆₃ Main belt: Kalliope (Linus) Euphrosyne Daphne (Peneius) Eugenia (Petit-Prince) Sylvia (Romulus · Remus) Minerva (Aegis · Gorgoneion) Camilla Elektra Kleopatra (Alexhelios · Cleoselene) Ida (Dactyl) Roxane (Olympias) Pulcova Balam Jupiter trojans: Patroclus (Menoetius) Hektor (Skamandrios) Eurybates (Queta) TNOs: Lempo (Hiisi · Paha) 2002 UX₂₅ Sila–Nunam Salacia (Actaea) Varda (Ilmarë) Gǃkúnǁʼhòmdímà (Gǃòʼé ǃHú) 2013 FY₂₇
Ranked by size	Planetary-mass moon Ganymede largest: 5268 km / 0.413 Earths Titan Callisto Io Moon Europa Triton Titania Rhea Oberon Iapetus Charon Umbriel Ariel Dione Tethys Dysnomia Enceladus Miranda Vanth Proteus Mimas Ilmarë Nereid Hiʻiaka Actaea Hyperion ...
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v t Moons of Saturn
Listed in approximately increasing distance from Saturn as of epoch JD 2459200.5.
Ring shepherds	S/2009 S 1 Ring moonlets Pan Daphnis Atlas Prometheus Pandora
Co-orbitals	Epimetheus Janus
G Ring	Aegaeon
Alkyonides	Methone Anthe Pallene
Inner large (with trojans)	Mimas Enceladus Tethys Telesto Calypso Dione Helene Polydeuces
Outer large	Rhea Titan Hyperion Iapetus
Inuit group (8)	S/2019 S 1 Kiviuq Ijiraq Paaliaq Saturn LX S/2004 S 31 Tarqeq Siarnaq
Norse group (46)	Phoebe Skathi S/2004 S 37 S/2007 S 2 Skoll Hyrrokkin Greip Mundilfari S/2004 S 13 (?) S/2006 S 1 S/2007 S 3 (?) Suttungr Saturn LIV Jarnsaxa Narvi Bergelmir Hati S/2004 S 17 (?) S/2004 S 12 (?) Saturn LIX Farbauti Thrymr Bestla S/2004 S 7 (?) Aegir Saturn LXI Saturn LV Saturn LVII Saturn LXII Saturn LVI S/2006 S 3 Saturn LXV Kari S/2004 S 28 Loge Saturn LXVI Fenrir Ymir Surtur Saturn LXIII S/2004 S 21 S/2004 S 39 S/2004 S 36 Fornjot Saturn LXIV Saturn LVIII
Gallic group (4)	Albiorix Bebhionn Erriapus Tarvos
Prograde outer satellites	S/2004 S 24
Rings of Saturn Cassini–Huygens Themis Chiron S/2004 S 6 S/2004 S 4 S/2004 S 3 In fiction