|Location:||Omicron Theta system|
Omicron Theta was the home to an Earth colony, the Omicron Theta colony. By 2328, this planet was a destination on commercial transport routes. In the colony, Dr. Noonian Soong and his wife Juliana perfected their positronic brain and successfully created a series of Soong-type androids including Data and Lore. The colonists discovered the evidence of ancient habitation in the mountains, which were excavated by archaeological field trips. (TNG: "Datalore", "Silicon Avatar", "Inheritance")
In 2336, both the planet and the Earth colony were devastated by the Crystalline Entity. A distress call was sent from the planet before all life on it was eradicated; the USS Tripoli was the only starship to respond but arrived too late, discovering a lifeless world. However, the Tripoli crew discovered the deactivated Soong-type android Data and reactivated him.
Along with finding the planet to be devoid of life and discovering Data, the Tripoli crew found what they believed were "dormant" plants. An analysis by an away team from the USS Enterprise-D determined that there was no soil bacteria. They also ascertained that Omicron Theta's plants were dead and not dormant. (TNG: "Datalore", "Rightful Heir")
Andrew Probert illustrated a handful of drawings to show how the set for Dr. Soong's lab might look. However, at least one of these concept artworks was labeled "Kiron III," the original name used for the planet. (Star Trek: The Magazine Volume 2, Issue 12, p. 49) (The planet's moniker was also Kiron III in the novelization of "Encounter at Farpoint"). In the script for "Datalore", the planet was identified as Data's Planet. Omicron Theta was the name of the system, not the planet.  This changed in "Silicon Avatar" when the planet, for the first time, was canonically identified as Omicron Theta. "ohm-ih-kron THAY-tah" was the pronunciation for this planet's name from the script pronunciation guide.