A star system where the Enterprise-D observed the collision of two gas giant planets in 2369, a rare event expected to ignite a new star.
The Detrian system is a star system featured in the sixth-season Next Generation episode Ship in a Bottle.
In 2369 the Enterprise-D travels there to watch two gas giants collide. Their combined mass is expected to be enough to start fusion and so give birth to a small star, something Starfleet has never been able to observe at close range. The ship takes up a carefully chosen position to record it.
The timing gives urgency to the main story. The holodeck character Professor Moriarty, reawakened after years in storage, appears to walk off the holodeck and seizes control of the ship, refusing to release it as the collision nears unless a way is found to bring the Countess Regina Bartholomew out as well. Picard eventually realises that he, Data and Barclay never left the holodeck.