Ymir (moon)

Ymir is a retrograde irregular satellite of Saturn. It was discovered by Brett J. Gladman, Kavelaars, et al. on August 7, 2000, and given the temporary designation S/2000 S 1. It was named in August 2003 after Ymir, the primordial giant from Norse mythology, from whose body the world was created.

Ymir is the largest of Saturn's irregular satellites, with a diameter estimated at about 18 km (11 mi). It orbits Saturn at an average distance of approximately 23.1 million kilometers in about 1314 Earth days.

Its retrograde orbit, high inclination (about 172 degrees to the ecliptic), and orbital parameters suggest that Ymir is a member of the Norse group of irregular satellites. The Norse group satellites are believed to have originated from the breakup of a larger body that was captured by Saturn's gravity.

Little is known about Ymir's composition. Based on its albedo, it is likely composed of ice and rock. Further observations are needed to better understand the surface properties and formation history of this distant moon.