Image of European Southern Observatory's La Silla observation site

This moon was discovered with a telescope located European Southern Observatory's La Silla observation site. La Silla, in the southern part of the Atacama desert, 370 miles (600 kilometers) north of Santiago de Chile, was ESO's first observation site. The telescopes are 7,870 feet (2,400 meters) above sea level, providing excellent observing conditions. Image Credit: ESO

Discovery

Paaliaq was discovered on Aug. 7, 2000, by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns at the European Southern Observatory in La Silla, Chile. They discovered Ymir and Kiviuq at the same time.

Overview

Paaliaq has a mean radius of 6.8 miles (11 kilometers), assuming an albedo (a measure of how reflective the surface is) of 0.06. At a mean distance of 9.3 million miles (15.0 million kilometers) from Saturn, the moon takes about 688 Earth days to complete one orbit. It has the most eccentric orbit around Saturn, meaning that its orbit is shaped like an oval.

Paaliaq is one of five known members of the Inuit group of moons, which orbit Saturn at a mean distance of 7 to 11 million miles (11 to 18 million kilometers), at inclinations between 40 and 50 degrees from the plane of Saturn's equator, and with eccentricities of 0.15 to 0.48. (A moon's eccentricity is a number between 0 and 1 which describes the shape of the orbit. The closer to 0, the more circular it is; the closer to 1, the more elongated.)

The Inuit moons all have prograde orbits (they travel around Saturn in the same direction as the planet's rotation), but their deviations from circular orbits and from the plane of Saturn's equator classify them as "irregular" moons. Like Saturn's other irregular moons, they are thought to be objects that were 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.

The similarities among the Inuit group's orbits suggest a common origin—they may be fragments of a single object that shattered in a collision. The other members of this group are Kiviuq, Ijiraq, Siarnaq, and Tarqeq.

Observations by Tommy Grav and James Bauer using telescopes on Mauna Kea, Hawaii in 2006 (before the discovery of Tarqeq) found that Kiviuq, Siarnaq and Paaliaq all are light red with similar infrared features, further supporting the idea of a common origin.

How Paaliaq Got Its Name

Originally called S/2000 S2, Paaliaq was named for a fictional Inuit shaman in the book, "The Curse of the Shaman," by Michael Arvaarluk Kusugak and Vladyana Langer Krykorka. Kusugak is responsible for the names of four of the five known moons in the Inuit group. He wrote the book from which the name Ijiraq was taken, and he suggested the names Kiviuq and Siarnaq, which came from Inuit legend and mythology.

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