Pasithee was discovered on Dec. 11, 2001, by Scott S. Sheppard, David C. Jewitt and Jan T. Kleyna at the Mauna Kea Observatory in Hawaii.


Pasithee is a member of the Carme group, a family of Jovian satellites which have similar orbits and appearance and are therefore thought to have a common origin. The group probably began as a D-type asteroid (possibly from the Hilda family or the Jupiter Trojans) that suffered a collision, which broke off a number of pieces, either before or after being captured by Jupiter's gravity. The largest remaining chunk (still retaining 99 percent of the group's mass) was named "Carme," and the smaller pieces became the other 16 moons in the Carme group.

All of the Carme moons are retrograde, which means that they orbit Jupiter in the opposite direction from the planet's rotation. Their orbits are also eccentric (elliptical rather than circular) and highly inclined with respect to Jupiter's equatorial plane. They all are very similar in color -- light red -- except for Kalyke, which is considerably redder than the others. All of these characteristics support the idea that the Carme satellites began as a captured asteroid, rather than forming as part of the original Jupiter system. None of the Carme members is massive enough to pull itself into a sphere, so they are probably all irregularly shaped.

Pasithee has a mean radius of about one kilometer. At a mean distance of about 14 million miles (23 million kilometers) from Jupiter, the satellite takes about 719 Earth days to complete one orbit.

How Pasithee Got Its Name

Originally called S/2001 J6, Pasithee was named for one of the Graces, who were daughters of Zeus, the Greek equivalent of the Roman god Jupiter. Her name (also spelled "Pasithea") means "kind to everybody." According to Homer's "Iliad," Pasithee was given in marriage to Hypnos (god of sleep) by Zeus' wife, Hera. Hypnos received Pasithee's hand in marriage as a reward for putting Zeus to sleep so that Hera could help the Greeks in their war against the Trojans.

A name ending in "e" was chosen for this moon in accordance with the International Astronomical Union's policy for designating outer moons with retrograde orbits.

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