Zeta Doradus system

"The Zeta Doradus system. There is a peculiar lack of data."

- Jerrod

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 system is relatively unknown to the UNSC.

History
The Zeta Doradus system was first explored in sometime around May 2491. The UNSC Engineering Corps discovered that all planets in the system were uninhabitable, except for Onyx. When massive subterranean Forerunner constructions were found on Onyx, the Office of Naval Intelligence took control of the planet. Onyx was removed from the UNSC navigational databases and the system was considered not a part of human space. ONI began to attempt to uncover the Forerunner artifacts on Onyx. The planet was also used as a training grounds for the SPARTAN-IIIs. The  was refit to serve in a conflict near Zeta Doradus in 2550.

In 2552, the three-sided Battle of Onyx was fought in the system between the Covenant, UNSC, and the Onyx Sentinels. All sides took massive casualties. Towards the conclusion of the battle, Onyx itself disintegrated, only leaving the shield world in its core intact. The shield world was located inside a slipspace bubble within Onyx. With the help of several Huragok, the shield world was brought back into normal space inside the system and renamed Trevelyan. It is unknown how Zeta Doradus fared once Trevelyan entered normal space.

Trivia
Dorado is an actual constellation, and it does possess a Zeta Doradus within it.

List of appearances

 * Halo: The Fall of Reach
 * Halo: Ghosts of Onyx
 * Remember Reach
 * Birth of a Spartan
 * Halo: Reach
 * Data pads
 * Halo: Glasslands