Aldebaron III was the inhabited third planet of its star system. This Federation planet was the home to the Aldebaron Colony and a Starfleet installation.
In 2265, the USS Enterprise made a stopover at this planet to pick up Dr. Elizabeth Dehner from the Aldebaron colony. (TOS: "Where No Man Has Gone Before")
In 2371, the Ferengi Belongo, nephew of Grand Nagus Zek, was detained on Aldebaron III by the local Starfleet authorities. (DS9: "Past Tense, Part I")
StarTrek.com and the Star Trek Encyclopedia, 4th ed., vol. 1, p. 16 – in an article about the Aldebaran system – treated Aldebaron III and Aldebaran III as the same planet. [1](X)
"al-DEB-uh-ron" was the pronunciation for this planet's name from the script pronunciation guide for "Past Tense, Part I". [2]
The closed caption from the episode on DVD gave the name as Aldebaran III.