Inuit group

The Inuit group is a dynamical grouping of the prograde irregular satellites of Saturn which follow similar orbits. Their semi-major axes range between 11 and 19 Gm, their inclinations between 45° and 50°, and their eccentricities between 0.11 and 0.39. They take an average of 2 years to orbit Saturn.

Animation of Saturn's Inuit group of satellites
   Kiviuq ·    Ijiraq ·    Paaliaq ·    Siarnaq ·   Tarqeq

Diagram illustrating the orbits of the irregular satellites of Saturn, showing the three Inuit subgroups. The inclination and semi-major axis are represented on the Y and X-axis, respectively. The satellites with inclinations below 90° are prograde, those above 90° are retrograde. The X-axis is labeled in terms of Saturn's Hill radius.

The International Astronomical Union (IAU) uses names taken from Inuit mythology for these moons.

The group appeared quite homogeneous in early observations, the satellites displaying light-red colour (colour indices B−V = 0.79 and V−R = 0.51, similar to that of the Gallic group)^[1] and similar infrared spectra.^[2] Recent observations, however, revealed that Ijiraq is distinctly redder than Paaliaq, Siarnaq and Kiviuq. In addition, unlike the other three, Ijiraq's spectrum does not display weak absorption near 0.7 μm. This feature is attributed to a possible water hydration.^[3]

The spectral homogeneity (with the exception of Ijiraq) is consistent with a common origin in the break-up of a single object but the dispersion of the orbital parameters requires further explanation. Recently reported secular resonances among the members could provide the explanation of the post-collisional dispersion.

Names

The twelve known members of the Inuit group are (sorted by distance from Saturn in their respective subgroups):

Name	Diameter (Km)	Period (days)[4]
S/2019 S 1	6	445.51
Kiviuq	19	449.13
S/2005 S 4	5	450.22
S/2020 S 1	4	451.10
Ijiraq	15	451.46
Paaliaq	30	687.08
S/2004 S 31	5	866.10
Tarqeq	7	884.98
S/2019 S 14	4	893.14
Siarnaq	39.3	895.87
S/2020 S 3	3	907.99
S/2020 S 5	3	933.88

In addition, S/2019 S 6 has also been categorized in the Inuit group by some sources.^{[lower-alpha 1]}

See also

• List of natural satellites

Notes

1. JPL's mean orbital elements suggest an inclination that is similar to those of the Gallic group; however other sources say it belongs to the Inuit group.

References

1. Grav, Tommy; Holman, Matthew J.; Gladman, Brett; Aksnes, Kaare (November 2003). "Photometric Survey of the Irregular Satellites". Icarus. 166 (1): 33–45. arXiv:astro-ph/0301016. doi:10.1016/j.icarus.2003.07.005 – via ArXiv.
2. Grav, Tommy; Holman, Matthew J. (2004-04-20). "Near-Infrared Photometry of Irregular Satellites of Jupiter and Saturn". The Astrophysical Journal. 605 (2): L141–L144. arXiv:astro-ph/0312571. doi:10.1086/420881. ISSN 0004-637X – via ArXiv.
3. Grav, Tommy; Bauer, James (2007-11-01). "A deeper look at the colors of the Saturnian irregular satellites". Icarus. 191 (1): 267–285. doi:10.1016/j.icarus.2007.04.020 – via ArXiv.
4. "Planetary Satellite Mean Elements". Jet Propulsion Laboratory. California Institute of Technology. 25 January 2024.

External links

Mean orbital parameters: from JPL