The Zeta Doradus system is a planetary system near UNSC-controlled space, approximately 38 light-years from Sol. It contains many planets orbiting the star Zeta Doradus, almost all of which are icy rocky planets or gas giants, none of which are habitable. The one exception, however, is the artificial planet known as Onyx. The cruiser UNSC Pillar of Autumn was refit to serve near Zeta Doradus in 2550. In 2552, the Battle of Onyx was fought in the system.