Sigma Ancylon is an uninhabited star system located on the edge of The Verge nearest to Federation space, and serves as the Federation's staging area in the region. The system centers around a binary star/black hole, Sigma Ancylon AB, which is orbited by five planets.

Due to the high levels of X-ray radiation emitted by the binary, the planets in this system are sterile, thereby reducing the chances of the Federation's presence being disruptive to any indigenous cultures.

The X-Ray Binary

Sigma Ancylon AB is a low-mass X-ray binary, consisting of the donor star Sigma Ancylon A and the accretor singularity Sigma Ancylon B. The star is an orange dwarf of spectral type K and luminosity class V, with a surface temperature between 3,900 and 5,200 K. It is composed primarily of neutral metals and has a solar mass of 0.76.

The Strand

The Sigma Ancylon system is also the nominal terminus for The Strand – an unstable wormhole leading to The Verge from Federation space – although in reality, the terminus' exact location fluctuates wildly.