Detria II

From Memory Alpha, the free Star Trek reference

Detria II was a planet in the Detrian system, classified as a gas giant.

In 2369, Detria II collided with another, bigger gas giant in the system, Detria VI; through a fusion reaction this collision gave birth to a new star. (TNG: "Ship in a Bottle")

The planet was identified "Deltria II" on an LCARS display of the collision.