Surtur was discovered on March 6, 2006, by Scott S. Sheppard, David C. Jewitt and Jan T. Kleyna using the Subaru 8.3-m reflector telescope on Mauna Kea, Hawaii.


Surtur has a mean radius of 1.9 miles (3 kilometers), assuming an albedo (a measure of how reflective the surface is) of 0.04. It orbits Saturn at an inclination of about 169 degrees and an eccentricity of about 0.4. At a mean distance of 14.2 million miles (22.9 million kilometers) from Saturn, the moon takes about 1,296 Earth days to complete one orbit.

Surtur is a member of the Norse group of moons. These "irregular" moons have retrograde orbits around Saturn — traveling around in the opposite direction from the planet's rotation. Surtur and the other Norse moons also have eccentric orbits, meaning they are more elongated than circular.

Like Saturn's other irregular moons, Surtur is thought to be an object that was captured by Saturn's gravity, rather than having accreted from the dusty disk that surrounded the newly formed planet as the regular moons are thought to have done.

How Surtur Got Its Name

Originally called S/2006 S7, Surtur was named for Surt, who guards Muspell, the land of fire in Norse mythology. At the doomsday time known as Ragnarok, he is destined to lead the fire giants in battle against the gods. The gods will be vanquished and Heaven and Earth will be consumed in fire.

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