Welcome to the Bolarus Sector :)
In this sector we start with Holberg 917G (sometimes known as Omega, but there are a couple Omega’s in Trek)…I chose a white dwarf for this system because a quick search for astronomers established that currently there is a Dr. Jay Holberg who seems to specialize in dwarf stars. So, short of asking Dr. Holberg what his choice would be for Holberg 917G, this particular star (Wolf 489) *could* be a future reference to another catalog that Dr. Holberg develops in the future :) — anyway, this system is the location for the TOS episode, “Requiem for Methuselah“
A couple light years away we have Merak, which (in theory) would be at Beta UMa…but, that real star is once again not actually located in a sensible location given the TOS reference for this system, the episode called “The Cloud Minders“…which moves us on to the Ardana system and the floating city of Stratos lording it up over the Troglytes down on the surface doing the dirty mining.
Between Ardana and Merak, but closer to Merak is the titular system for the sector, Bolarus…home of the Bolians, located at the Beta Comae Berenices.
The actual real life star Arcturus is located in this sector.
A few light years from Arcturus is Starbase 21, which the Enterprise traveled to directly after the TAS episode, “How Sharper Than a Serpents Tooth.” So in theory that episode occurred in open space somewhere within a few light years of the GL 542 star system where SB 21 is located.
About half of “The Barrens” is located in the Bolarus Sector; the events of the ENT episode “Daedalus” take place somewhere within a few light years of coordinates 3X,27Y. As with the reference to the size of the Delphic Expanse, it is assumed that the reference to the size of The Barrens is one of cubic proportions instead of straight linear distance across.
Also in this sector are the STO systems: Breshnar, NGC 1218, Ponor, Llaiir, Rashana, and Ch’menira.