The Ionian system was 13,000 light years away from the algae planet.
In their search for the Eye of Jupiter's function and symbolism, Lieutenant Felix Gaeta discovers that a nova occurred in the Ionian system which was seen 4,000 years ago, around the time the 13th tribe left Kobol. The nova left behind a gas cloud, known to the Colonials as the Ionian nebula (Rapture).