(written from a Production point of view)
It was identified in the final draft script for the Star Trek: The Animated Series first season episode "The Time Trap", dated 19 October 1973. According to the script notes, Magen is said to have originated from the Omega Cygni system, and that her planet is described as "one of light gravity." This information would later appear in Star Trek Concordance, which combines this information with that of the Omega Cygni mentioned in "Mudd's Passion". This information is also stated in the Alan Dean Foster novelization of the episode in Star Trek Log 4 and later in Star Trek: SCE.