The Pasiphae group: Jupiter’s loosest moon family

Why astronomers are less sure all of Pasiphae’s companions share one origin.

Published 2026-10-23

Autonoe belongs to the Pasiphae group, a family of retrograde moons with similar orbits.^[2]

The orbits

Members have semi-major axes of roughly 22–25 million km, inclinations of 141°–158° and eccentricities of 0.22–0.44.^[1]

A parent body

The original body is calculated to have been about 60 km across, about the size of Pasiphae, which retains 99% of its mass — or 87% if Sinope belongs to the group.^[4]

Less confidence

Compared with Jupiter’s other groups, confidence is lower that all Pasiphae-group moons came from a single collision, because of differences in colour and orbits.^[2]

Resonances

The group’s position is subject to scattering by mean-motion resonances with Jupiter’s orbit, which may explain its spread.^[4]

Numbered citations link to the sources list on the Autonoe overview page.