Castor and Pollux in the sky

From Saturn’s moon to the Gemini twins.

Published 2026-10-23

Polydeuces is another name for Pollux, twin of Castor and son of Zeus and Leda.^[1]

The moon’s name

The IAU approved the name on 21 January 2005; its earlier designation was S/2004 S 5.^[1]

A tiny namesake

NASA lists a mean radius of just 1.3 km.^[2]

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