Lexor

Lexor was the name of a planet that Lex Luthor traveled to years ago and while he was there he fell in love with a woman named Ardora and he married her and impregnated her with a child. Years later he returned and met his young son, Lex Luthor, Jr.

Eventually, a terrible accident caused the entire planet of Lexor to be destroyed, and Ardora and his son are both killed along with all of the other natives of the planet. Lex Luthor blames Superman for their deaths, even though he is not actually responsible.

Reference
Super Powers (Volume One)
 * Super Powers Vol 1 1