Background information Edit
Star Trek Maps, Star Trek Concordance and an entry on Startrek.com referred to the planet mentioned in "Wolf in the Fold" as "Alpha Proxima II". The pronunciation of this planet in the episode sounded more like "Alpha Aradoni II", which was also supported by the closed captioning. The spelling of "Alpha Eridani II" can be found in the Redjac entry on Startrek.com and in the Star Trek Encyclopedia as well as the Star Trek: Star Charts. According to Star Trek Maps (pg. 22), Alpha Proxima II was one of the first extra-solar Human colonies, with major industries in mining, farming and sea-farming. By the 23rd century, the planet had a total population of 12 million with more than 3 million living in the port city Heliopolis.
Taking place in the late 24th century, the novels Articles of the Federation and Rough Beasts of Empire, as well as the Star Trek Maps and Star Trek: Star Charts seem to place the star Achernar within the Romulan Star Empire. Note, however, that Achernar (Alpha Eridani) is a real star and, as depicted in Star Trek: Star Charts, may appear to be located inside Romulan space but, given its real distance to SOL, which is about 140 light years, it is actually about 120 light years "below" the sector plane; that is about six full sectors "below" it. Therefore, it may very well be outside of claimed Romulan space, that is, "below" it, and, therefore, Alpha Eridani II may still be inhabited by the descendants of Earth natives. It also describs Achernar as a binary star system, consisting of two B-class components with a magnitude of +1 (hundred times brighter than Sol).