An eight-hour day

Bergelmir’s rotation and what it tells us.

Published 2026-10-23

Bergelmir rotates once every 8.13 ± 0.09 hours.^[1]

How it’s measured

Rotation periods come from light curves — graphs of brightness over time.^[1]

Small and dark

NASA estimates Bergelmir’s radius at about 3 km, assuming an albedo of 0.04.^[2]

Captured

Like Saturn’s other irregular moons, Bergelmir is thought to have been captured rather than formed around Saturn.^[2]

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