Wikipedia
Siarnaq , or Saturn XXIX, is a prograde irregular satellite of Saturn. It was discovered by Brett J. Gladman, et al. in 2000, and given the temporary designation S/2000 S 3. Named after the giant Siarnaq of Inuit mythology, it is the largest member of the Inuit group of irregular satellites.
Siarnaq is thought to be about 40 kilometers in diameter. It orbits Saturn at an average distance of 17.5 Gm in 895 days. The rotation period was measured by the Cassini spacecraft to approximately 10 hours and 9 minutes; this is the shortest rotation period of all prograde irregular moons of Saturn.
It is light red in color, and the Siarnaupian (Siarnaqan) spectrum in the infrared is very similar to the Inuit-group satellites Paaliaq and Kiviuq, supporting the thesis of a possible common origin in the break-up of a larger body.
Siarnaq has been found to be in a secular resonance with Saturn, involving the precession of its periapsis and that of the planet. The studies of these resonances are key to understand the capture mechanism for the irregular satellites and, assuming a common origin of a given dynamical group in the break-up of a single body, to explain today’s dispersion of the orbital elements.
The ecliptic longitudes of the periapsis of the satellite and the planet are locked.