Chaltok IV

From Memory Alpha, the free Star Trek reference

Chaltok IV was a planet in Romulan space, the fourth planet in the Chaltok system.

Chaltok IV housed a Romulan research station in the 2260s. It was almost destroyed in a polaric energy explosion, which led to the signing of the Polaric Test Ban Treaty in 2268. (VOY: "Time and Again")