"It is our home. It defines who we are. If Kaelon II ceases to exist, so do we."
– Timicin, 2367 ("Half a Life")
Kaelon II was the inhabited second planet in its star system. This was the homeworld of the Kaelons, a warp-capable isolationist humanoid species.
The gradual expansion of the Kaelon sun into a red giant threatened to destroy or sterilize the planet by the 2390s, and the Kaelons directed their efforts to revitalize it, refusing to evacuate. In 2367, a leading scientist of their world was Dr. Timicin. (TNG: "Half a Life")
In 2371, the location of Kaelon II was labeled in the star chart Data and Picard were studying in stellar cartography aboard the USS Enterprise-D. (Star Trek Generations display graphic)
The Star Trek Encyclopedia, 4th ed., vol. 1, p. 398 and StarTrek.com classified Kaelon II as a M-class planet. [1](X)