DT-262 was a class R rogue planetoid located in or near Federation space in the galaxy's Alpha or Beta Quadrant.
History and specifics
DT-262 emitted undetermined forms of deadly radiation. It did not support life.
In 2269, the Federation starship USS Enterprise was assigned to study DT-262 as it passed through Sector 875. A temporal disruption resulted in James T. Kirk becoming unstuck in time and realizing that the planetoid's emissions were deadly to an advanced civilization in the sector.
With pinpoint phaser accuracy, Hikaru Sulu excavated a smooth concave depression 400 meters deep and 800 meters wide on the surface. Canisters of G-108 and HD-585 explosives were transported to the center of the depression. When detonated, the resulting controlled blast diverted the path of the planetoid, and it avoided endangering the sector's inhabitants.
The blast also avoided a divergent timeline in which the Enterprise was destroyed by temporal phase weapons. (TOS - New Visions comic: "Time Out of Joint")