Ijiraq (moon)
A red irregular moon of Saturn named after an Inuit creature.
Ijiraq, also known as Saturn XXII, is a small, prograde irregular moon of Saturn. It stands out among the Inuit group of irregular satellites because it is significantly redder than its companions Paaliaq, Siarnaq, and Kiviuq. Its spectral slope—a measure of how its reflectivity changes with wavelength—is twice as steep (20% per 100 nm), a trait typical of red trans-Neptunian objects like Sedna but unusual for irregular moons. Additionally, Ijiraq’s spectrum lacks the faint absorption near 0.7 μm that suggests water hydration, which is present in the other three.
The moon orbits Saturn at an average distance of 11.3 million km, completing one revolution in 451 days on a path very similar to that of Kiviuq. It is thought to be in a Kozai resonance, where its orbital inclination decreases cyclically while its eccentricity increases, and vice versa. The argument of its pericenter oscillates around 90° with an amplitude of 60°. Like Kiviuq and Thrymr, Ijiraq’s orbital elements heavily overlap with those of Phoebe, and a future collision with Phoebe is considered likely.
Discovered in 2000 by a team including Brett Gladman and John J. Kavelaars, it was initially designated S/2000 S 6. The moon was named in 2003 after the ijiraq, a creature from Inuit mythology. Kavelaars, an astronomer at McMaster University, proposed the name to help move astronomical naming beyond its Greco-Romano-Renaissance tradition. After months of searching for multicultural, Canadian-appropriate names and consulting Amerindian scholars without success, he found inspiration while reading an Inuit tale to his children in March 2001. The ijiraq plays hide-and-seek, which Kavelaars felt suited these elusive, cold moons—the discovery team included Canadians, Norwegians, and Icelanders, all sharing a nordic connection. He contacted the tale’s author, Michael Kusugak, for permission; Kusugak also later suggested the names for Kiviuq and the dwarf planet 90377 Sedna.
Quick Facts
- Discoverer
- J. J. Kavelaars / B. J. Gladman
- Discovered
- 2000
- Mpc Name
- Saturn XXII
- Pronounced
- ˈ · ɪ · dʒ · ɪ · r · ɑː · k
- Named After
- Ijiraq
- Epoch
- 2000 January 1.5
- Semimajor
- 11.3447 Gm
- Eccentricity
- 0.293
- Period
- 451.12 d / (1.24 yr)
- Inclination
- 49.2°
- Satellite Of
- Saturn
- Group
- Inuit group (Kiviuq)
Facts from the source article.
Lore & Background
Ijiraq was discovered in 2000 by the team of Brett Gladman, John J. Kavelaars, et al., and given the temporary designation S/2000 S 6. It was named in 2003 after the ijiraq, a creature in Inuit mythology. Kavelaars suggested the name to help astronomical nomenclature move beyond its Greco-Romano-Renaissance tradition; he spent months seeking multi-cultural Canadian names, consulting Amerindian scholars without success. In March 2001, while reading an Inuit tale to his children, he had a revelation: the ijiraq plays hide-and-seek, mirroring how these small moons are hard to find, and they are cold like the Canadian arctic. Kavelaars contacted the tale's author, Michael Kusugak, who gave his assent and later suggested names for Kiviuq and 90377 Sedna.
Ijiraq orbits Saturn at an average distance of 11.3 million km in 451 days on an orbit very similar to Kiviuq's. It is believed to be in Kozai resonance, cyclically reducing its inclination while increasing eccentricity and vice versa, with its orbital argument of pericenter oscillating around 90° with an amplitude of 60°. Its orbital elements overlap strongly with those of Kiviuq, Thrymr, and Phoebe, and it is likely to collide with Phoebe in the future.
Physically, Ijiraq is a member of the Inuit group of irregular satellites, but recent observations show it is distinctively redder than Paaliaq, Siarnaq, and Kiviuq. Its spectral slope is twice as steep (20% per 100 nm), typical for red trans-Neptunian objects like Sedna but unknown for irregular satellites. Additionally, its spectrum lacks the weak absorption near 0.7 μm attributed to possible water hydration that is found in the other three.
Reader's Guide
Ijiraq's significance lies in its distinctive spectral properties among Saturn's irregular satellites. As a member of the Inuit group, it shares orbital similarities with Kiviuq, Thrymr, and Phoebe, but its redder color and steeper spectral slope set it apart, being typical of red trans-Neptunian objects like Sedna and unknown for irregular satellites. This suggests a different surface composition or origin. The absence of a water hydration absorption feature further distinguishes it from Paaliaq, Siarnaq, and Kiviuq. Its naming history reflects a deliberate effort to diversify astronomical nomenclature beyond Greco-Romano-Renaissance traditions, rooted in Canadian and Inuit culture. The name was chosen by discoverer John J. Kavelaars after reading an Inuit tale to his children, with the creature's hide-and-seek nature mirroring the moon's elusiveness. The involvement of Michael Kusugak, the tale's author, who also suggested names for Kiviuq and Sedna, ties Ijiraq to a broader cultural narrative. Its likely future collision with Phoebe underscores the dynamic and evolving nature of Saturn's moon system.
Did You Know?
- Its spectral slope is twice as steep as that of other Inuit-group satellites, at 20% per 100 nm.
- Ijiraq's orbit overlaps strongly with Phoebe's, and it is likely to collide with Phoebe in the future.
- The name was suggested by Kavelaars after reading an Inuit tale to his children, with the author Michael Kusugak's assent.
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